California Endures Storms Again Today, But It's Finally Ending

A home buried in mud and rocks after a
debris flow in Wrightwood, California
Widespread storms and atmospheric
rivers have plagued California
for more than a week now 

The giant storm in California is starting to ease today, after causing days of havoc from the Oregon border all the way down to Mexico. 

The storms targeting southern California over the Christmas holiday have so far claimed at least three lives. 

Another person died in San Diego when a large tree branch fell on him, reported television station KGTV.  At least 90 trees fell across the city of San Diego. 

Videos are at the bottom of this post. 

A number of people were plucked from flooded cars on streets and highway throughout southern California. 

One of the hardest hit areas is the community of Wrightwood in the San Gabriel Mountains, where several homes were buried under several feet of mud, notes KTLA.

Video showed some houses with four feet of rocks and mud inside them. Cars were buried halfway up their windows Two people died and six others were injured on a wet freeway..

Downtown Los Angeles on Wednesday received 2.53 inches of rain, which is a bit more than what normally falls in the entire month of December. Other totals from just December 24 include 3.96 in Woodland Hills and 3.39 in Burbank. 

Before the storms hit the L.A area, the atmospheric rivers targeted northern California. Redding, California was probably the hardest hit. The city had 5.3 inches of rain from December 16 to 22, with much more in the higher elevations nearby. 

A 74-year old man died when he drove around barricades and got swept up in the flooding. 

High winds also tore through the Golden State. 

 Santa Cruz Harbor reported a gust to 91 mph. Several boats were not surprisingly damaged. Likely not a tornado, say NWS. Pablo Point, about 20 miles northwest of San Francisco reported a gust to 108 mph. 

About 125,000 people lost power in central and northern California over the Christmas holiday.  

Heavy snow has been falling in the Sierra Nevada range, with some places clocking in with several feet of snow.

Interstate 80 through Donner Summit was impassable at times over the holiday as vehicles got stuck, crashed or spun out. 

 Rain continues in southern California today, though it's not coming down as heavily as it did Wednesday and Thursday. But now that the ground is sodden from the storms, so the somewhat lighter rain could really set off more debris flows and mudslides. Los Angeles itself could get another one to two inches of rain today. The mountains could get another three inches. 

After that, practically no rain is expected in California until later Wednesday or Thursday. 

Videos:

A scary tour of flooded Redding, California on December 21. Click on this link to view, or if you see the image below, click on that. 

Next video shows a motorist stupidly driving into fast flowing water and getting swept away. So what does the next car do when they see this? Drive into the fast flowing water and get swept away. People are dumb. They were both eventually rescued, by the way. This was in Palmdale, California. Click on this link to view, as always, or if you see the image below, click on that. 

Aftermath of the huge debris flow in Wrightwood, California. Click on this link to view, or if you see the image below, click on that. 

California Storm Season Off To An Early Start: Flood, Mudslide, Debris Flow Fears Rise

Satellite view this afternoon that is menacing
 California with the threat of heavy rains and floods
Southern California in particular will see very
heavy rain for so early in its wet season
Debris flows near the sites of recent wildfires
are the biggest threat. 

 It's not just the eastern United States having an early start to winter. 

Storms coming off the Pacific Ocean this week are giving California an early start to their annual winter wet season.

The storms over the next few days are raising fears of urban flooding, mudslides and debris flows. Especially near the sites of large wildfires in recent years. 

The fun started today. Flood advisories were up in San Francisco along with coastal and slightly inland areas north to Fort Bragg and south all the way down to Santa Cruz.

 The heaviest rain was moving out of coastal northern California late this afternoon, so some, but mot all  of those advisories have been lifted. 

However, inland, near Sacramento and the rest of the Central Valley, flood advisories were still in effect late this afternoon. 

The heavy rain was moving inland to the Sierra Nevada foothills, where flood watches are in effect. 

Areas of northern California might see two to as much as six inches of rain through tonight. Higher up in the Sierra Nevada mountains, it's obviously colder, so winter storm warnings are up for parts of the Sierra. Some areas could get as much as a foot of snow.

That's not huge by Sierra Nevada standards, but it's pretty good for this early in the season. 

SOUTHERN CALIFORNIA

The real show starts later tonight and tomorrow and continues all week in southern California.

A huge ridge of high pressure is parked over the middle of the U.S. That will make a storm the storm that is trying to move eastward to affects southern California to do so only at a snail's pace. That means sunny L.A. and the rest of southern California are going to feel more like Seattle. 

Which isn't a good thing especially for the fire-scared hillsides of California. 

Los Angeles County has issued evacuation warnings for thousands of people who live near areas burned in recent wildfires. That includes last January's massive Palisades and Eaton fires. The warning is in effect from this evening through late morning Sunday. 

An evacuation warning means people should be ready to evacuate at a drop of a hat. They should spend today gathering documents, medications, important records, and supplies for a possible mandatory evacuation, and have arrangements made for children and pets. 

People who move slowly, like the elderly and disabled, should consider getting out of Dodge today before the rain really starts to fall. 

This all proves that a wildfire disaster isn't over after the last flames are extinguished. There's the risk of further damage - maybe extensive - months or years after the fire. I'll hate to see people whose homes survived the fire only to be wrecked by flash flooding and debris flows. We'll see how that goes. 

The National Weather Service this afternoon hoisted flood watches for all of southern California except for the extreme southeast corner. Most of the watches go into effect late Friday night and continue through Saturday night. 

Some forecasts predict the storms could dump up to seven inches of rain on the mountains north and east of L.A. For lower elevations, two to four inches of rain could fall, but those forecasts could change pretty radically up or down over the next day or two.

Most of the rain would come in two bursts, one tonight and part of tomorrow, the other focused on Saturday. 

At least the early onset of rainfall in southern California is tamping down the risk of more huge early winter firestorms like the region had last year. A very early season southern California rainstorm in mid-October helped. 

October ended with 0.8 inches of rain in L.A., which is above the normal of a half inch. 

Normal rainfall in Los Angeles in November is about 0.8 inches. It hasn't rained there yet this month, but this storm could really get the rainy season off to a good start. Total rainfall tonight through Sunday could reach two to as much as four inches in the Lost Angeles Basin.

The bulk of southern California's rain comes in December through the first part of March. It's obviously too early to know whether this rainy pattern will continue through the winter.

If not, and December and January turn dry, the risk of wildfires could return. In Southern California, it always seems likes it's either too little or too much rain.  

Oddly Early Winter Storm Snarls California, And Additional Rough, Wet Weather Hits Other Parts Of U.S. Southwest

Workers try to clear storm drains in San Francisco
Monday as cars splash through the deep puddles.
An oddly early, strong storm is hitting
Californian. Photo from the San Fransisco 
Chronicle, via Facebook.

 California is being hit today by the kind of storm they usually have to wait until January or February to see. 

The storm features locally heavy rains, the threat of debris flows and mudslides, heavy snow in the mountains and even a low but still real chance of a brief tornado in the Los Angeles basin. 

This type of storm hits California fairly regularly in the dead of winter, but they almost never happen this early in the season. 

The biggest threat from this storm is for people who live near and below the sites of those giant, deadly wildfires that hit the L.A. area last January. 

The City of Los Angeles issued evacuation warnings for homes near the fire burn areas in Pacific Palisades and Malibu, KTLA tells us. 

People who live near the site of a big January fire in and around Altadena were also told to be on the alert to possible evacuations. Same was true near other burn scars in Orange County. 

Valleys in southern California can expect an inch of rain, give or take, which is wildly big for October. The mountains and foothills can expect two to four inches. 

Normal rainfall for the entire month of October in Los Angeles is about a half inch. 

The biggest problem is that the rain in southern California should come in a relatively brief time, with most of it falling within four to six hours. Such downpours can really move rocks and dirt in areas where vegetation was destroyed by wildfires. 

As of 5:30 a.m local time, a gusty thunderstorm with downpours and gusts to 55 mph was blustering through the Los Angeles basin. Very odd for what is normally a dry time of year. 

Further north, the first snows of the season have started falling in the notoriously snowy Sierra Nevada mountains. 

By midwinter standards, this storm isn't huge. But for October, it's impressive. Snow levels were forecast to fall to 5,000 feet above sea level today. Interstate 80 through Donner Pass should have slushy snow and traffic delays along it today. Higher up, some ski resorts, though not open yet, can expect maybe a foot of snow. So I imagine some renegade skiers and riders will be up there doing their thing.

In the San Francisco Bay Area, torrential rains flooded roads and drowned cars in many areas. Several days, mostly Ubers and Lyfts leaving the airport, got trapped in flash flooding Monday night, ABC7 News in San Francisco reported. 

San Francisco on average receives 0.79 inches of rain during the entire month of October. More than that fell in just one day Monday, as the city received 0.87 inches, at least as measured at the airport. 

The oddly early preview of the California rainy season might or might not be good news for the fall and early winter wildfire season.

Strong, dry Santa Ana winds propel the ferocious wildfires in southern California. The worst of them hit from about now through mid December. (Last year, the lack of rain and the Santa Anas kept going well into January, hence the deadly mega fires in the L.A area).

Initially, everything will be damp, so the wildfire risk will be low. But the rain will inspire new plant growth - grass, weeds, that kind of thing. 

By this time of year, northern California is close enough to the normal storm track so that wildfire season is probably over up there. 

But in southern California, that new growth could dry out and become tinder for fires later this fall and early winter.  Southern California is not out of the woods for wildfires just yet. 

That's true even though the weird October rains in California might not be over. Another storm, smaller and weaker than the one they're getting now, could come through next Monday with a little more rain. After that, it seems California will revert back to its normal dry, sunny late October weather.

SOUTHWEST STORMS 

An intense microburst caused a lot of damage in
Tempe, Arizona Monday. It was part of a stormy
pattern in the normally dry southwest U.s. 

It's been a strangely stormy autumn in the Southwest this year, thanks in part to the remnants of Hurricane Priscilla, which originated off the west coast of Mexico. The storm remnants became Priscilla, the (very wet) queen of the desert.   

In Tempe, Arizona, an intense thunderstorm microburst Monday packing winds of at least 70 mph tore roofs off apartment buildings, mobile homes and businesses, displacing at least 130 people. Parts of warehouses collapsed, semi-trucks overturned, and power lines collapsed in the storm. Luckily, there were no serious injuries. 

Another microburst Sunday in Tucson, Arizona damaged several properties, blew over trees and saguaro cactus and caused flooding. The city received 1.2 inches of rain, the biggest storm in almost a year. 

On Sunday, flash floods damaged several homes in Mesa, Arizona and closed roads. 

The bad weather extended into New Mexico and Colorado, causing damaging flash floods in both states. 

In normally arid southwest Colorado, flash floods wrecked about 100 homes, prompted nearly a dozen high water rescues and blocked roads. As much as five inches of rain fell in that part of Colorado. Flooding also hit around Salt Lake City, Utah.   

Storm To Cause Problems Across U.S. Through The Weekend; Vermont In For A Lot Of....Something

Vermont Agency of Transportation posted
this photo to Facebook Thursday 
showing a backhoe shoving large
snowbanks away from Route 105 in
Jay around Richford Mountain to
make room for more plowed snow
in upcoming storms. 

 Our weird storm from earlier today is mostly done, as the snow we did get settled and got soggy in many places as temperatures went above freezing. 

Nice snowball and snowman making snow for a change, briefly. I saw a couple reports of five inches of snow near the Canadian border in the Northeast Kingdom, which is the most I've seen so far today. 

A few light rain showers in the valleys will change to scattered snow showers this evening without amounting to much. Water on roads and driveways should freeze up this evening, though so take care. 

IT's going to get windy tonight, too, so expect some many areas to see gusts over 40 mph.  The Vermont counties near the Canadian border and in far southern Vermont are under wind advisories, with possible gusts to 55 tonight. 

There might be a power outage or two with that kind of wind, though I'm guessing nothing too widespread. 

After a blustery, cold Friday, we gear up for the long awaiting larger weekend storm. 

First, the big picture

NATIONWIDE DANGER

Our storm is starting to cause its trouble today in California. 

California Flood/Debris

Flooding is possible today anywhere near the entire California coast and in the lower foothills of the Sierra Nevada, below the level where heavy snow is falling.

Southern California is the real trouble zone, thanks to the recent giant wildfires there. Rainfall rates are forecast to be between a half inch to an inch an hour at times, with rainfall totals in the three to six inch range. 

This would be enough to set off some mudslides and flash flooding without the prior wildfires. Now, with the huge burn areas devoid of vegetation and the soil cooked in such a way by the fires that water can't soak in well, the runoff is sure to create large debris flows.  The worry is it will destroy or damage homes that somehow escaped the fire. 

Fire officials have evacuated homes and businesses near the sites of the fires as a precaution. 

Eastern Flood

Once this storm is done with California, its destructive flooding won't end. Forecasters are worried about potentially serious flooding from Louisiana and other areas of the Southeast on up through the Tennessee Valley, West Virginia and southern Ohio,

This area has had a lot of precipitation from the parade of storms that have blown through this region all month.  Rivers are running high, soils and saturated. Now, three to six inches of rain is forecast Saturday in this region, 

There's already a level three "moderate" alert on a four point scale for flooding in this region. It's rare to issue that high a risk a couple days in advance.  NOAA's Weather Prediction Center is considering raising this to a rare "high risk" alert level for flooding. 

High risk is reserved for only the most dangerous flash flood scenarios. (They put Vermont under a high risk alert for the catastrophic flooding on July 10, 2023, for instance).

This could be a deadly and highly destructive flood, and it could hit some of the areas trashed by the extreme floods of Hurricane Helene back in September. 

Severe weather/tornadoes

Forecasters are also worried about a pretty widespread outbreak of severe thunderstorms and tornadoes near the Gulf Coast and Southeast Saturday with this new storm. There were already a handful of tornadoes with the most recent storm yesterday, and this one could prove more widespread. We'll need to watch for updates because of things come together correctly, they could end up with strong, long lasting tornadoes

And of course, along and to the north of this strong storm, freezing rain, sleet and snow will fall in torrents in a wide area stretching from Great Lakes to southeast Canada. Current forecasts call for wide areas of ice in the Ohio Valley, Mid-Atlantic and Northeast. 

Which leads us, finally, to what the hell is going to happen here in Vermont with this storm. 

VERMONT EFFECTS

Disappointingly, we don't know exactly how this will play out. Once again, it's going to be one of those marginal situations between snow, ice and rain

This will be different from all the quick hitters we've had this month. The weekend storm should stick around for awhile. As of this afternoon, it looks like something will be coming out of the sky in Vermont from Saturday evening at least until early Monday morning. 

One depiction of where this weekend's expected
strong storm might be Sunday morning. Exactly
where it goes, and how much warm air
intrusion aloft comes with it will determine
if Vermont gets a lot of snow, or a nasty
mix of frozen stuff. 

The storm itself will also be much stronger than the ones that have blown through here lately. 

At some points in this storm, we're going to have to deal with strong winds in some places. Best guess is early on in the storm, maybe Saturday nigh and early Sunday, strong downslope winds might hit the western slopes of the Green Mountains. 

Behind the storm, we could be dealing with strong, cold northwest winds. 

Like the storm we had Thursday, the temperature profile in different layers of the atmosphere over Vermont will be complicated. 

 We're going to see revisions right up through the storm as to how much snow, how much sleet and freezing rain, and even how much regular rain different parts of Vermont might see.

The early read on this is the main storm will head in from Ohio, across northwest Pennsylvania and into New York and maybe Vermont. A second storm will also start to develop along the New England coast.

How these two systems interact, and how far west the original storm goes, will dictate how much snow we get, versus how much sleet, freezing rain and rain.

There's a still a chance this could remain all or mostly snow, especially in the far north, but we just don't know yet. The best chances of an ugly mix are in southern Vermont.  For the record, the National Weather Service for now is going with mostly or exclusively snow north, and a mix south. 

It does look like it will start as snow for all of us Saturday, with the snow getting heavier later at night. Then we might get the mix, depending on temperatures. The tail end of the storm later Sunday or Sunday night looks like it could provide a decent burst of heavy snow. Maybe. 

I'm not even going to guess on how much snow and/or ice we're going to see out of this.  For now, I'd consider putting travel plans on hold this weekend. Especially on Sunday, when the worst of it looks like it wants to come through. 

This could be the strongest winter storm we've had all season, but what form it will take is ridiculously tricky. 

California Rain Benefitted Greatly, But Not All That Much Rain Set Off Burn Area Debris Flows

To virtually everyone's relief in southern California, 
rain arrived as expected to tamp down those horrible
wildfires. The fires left the area prone to debris flow
in the rain, though, and some did in fact materialize.

 After going 262 days without any rain, showers finally blew through Los Angeles Sunday. 

The showers -which included small hail in some sections of the city and snow in the mountains - was a tremendous relief to everyone dealing with this month's wildfire nightmare in southern California. 

Though greatly beneficial, the rain, as expected in some ways continued the wildfire nightmare for some.

The rain storm hasn't been that big by southern California standards. Los Angeles just under an inch of rain from the weekend system. It was the first real rain the city has had since March 20.  

With the fires, that was enough to set off mudslides. One of the largest was in Topanga Canyon near the site of the big Palisades fire. 

Another mudslide poured down onto Mulholland Drive in Woodland Hills, trapping at least four vehicles in muck and rocks. A Los Angeles city fire truck also had to be pulled from the morass. 

This particular mudslide thankfully didn't damage any homes. 

A small section of the Pacific Coast Highway also had to be shut down due to mud and debris pouring onto the roadway. 

The rain obviously tamped down the fire and finally prevented new ones from starting, at least for now. The largest fires from this month are now almost entirely contained and are just barely smoldering in the damp conditions. 

Extended forecasts call for a few more chance of rain over the next couple of weeks.  Those extended forecasts lean slightly toward above normal precipitation in central and northern California and near normal in still much to dry southern California. 

Video

News station aerial view of one of the mudslides due to fire-denuded hills and the rain over the weekend. Click on this link to view, or of you see the image below, click on that

California Fires Kept Popping Up, Spreading, But Finally Rain Starting Later Today

A photo from Reuters of the Hughes Fire, another massive
wildfire that broke out in California this week. The Hughes
Fire, thankfully, did not mow down neighborhoods.
Finally, rain is in the Southern California
forecast for this weekend. 

It's been whack-a-mole all week with wildfires breaking out in southern California. 

Meanwhile, millions of people in that region are looking to the skies later today and tonight looking for the promised raindrops. 

More on that in a bit.

THE FIRES

A slew of new fires kept areas near Los Angeles and San Diego seriously rattled Wednesday, Thursday and Friday and kept air quality unhealthy. 

Perhaps the largest of the new blazes, known as the Hughes Fire, covered more than 10,000 acres as it spread rapidly in and near the Santa Clarita Valley Wednesday night and Thursday. It sent thousands of residents fleeing under evacuation orders

So far, I've heard of few, if any houses burned by this fire, which is great news. 

Another fast moving fire prompted evacuations and threatened California State University Channel Islands in Ventura County.  That fire was being gradually tamped down Friday and classes resumed the university after being canceled Thursday.   

Another large fire was burning out of control in San Diego County right near the Mexican border. That fire was initially fast-spreading and erratic, and prompted evacuations, but firefighters had slowed its progress by Friday afternoon. 

It's been another trying week in California, but at least this time, whole neighborhoods have not been wiped out in the new fires so you have to take any good news you can. 

THE RAIN

Miraculously, earlier forecasts of a rainy Southern California weekend have not evaporated. It's still going to rain. 

This won't be any kind of huge storm, as most places in the Los Angeles and San Diego areas should received about a half inch to an inch of rain between now and Monday. 

That is unequivocally awesome news, but of course, this being California, the rain comes with its own risks.

For the vast majority of the southern California, the rain will just wet down tinder dry vegetation, but not be heavy enough to cause any mudslides or flooding.

The problem is where there's been wildfires. It wouldn't take much to set off debris flows in these areas, since the vegetation that held steep hillsides in place is gone. The surface of the soils have been cooked hard by the fires, meaning rainwater can't penetrate, it will just run off downhill, collecting more and more debris along the way. 

It's amazing that the NOAA's Weather Prediction Center felt the need to place a marginal risk of flash flooding through the weekend in southern California areas that have been burning for the past month. But there you go. 

The National Weather Service office in Los Angeles is giving a 10 to 20 percent chance of significant debris flows in recent burn scar areas. Those odds seem low-ish, but are actually pretty high if you consider the grave danger they pose to anybody or any property in the path of these things. 

The hope is the rain will just fall gently and steadily, and not in short, sharp downpours. 

As of this morning, it looks like the region will get a little bit of both styles of rain. It will rain in most places at a rate of something like a tenth of an inch per hour, which isn't a big deal. 

But a very cold pool of air aloft means thunderstorms could easily develop. Under those storms, a half inch to three quarters of an inch of rain could come down within an hour. If that happens over a recent burn area, you're going to get debris flows. 

Even if there are no major debris flows, runoff could spread toxic ash from fire zones into areas not directly affected by the wildfires. 

One last concern: This rain won't get rid of the drought that's developed in California. Worse, this could be a "one and done" storm. Some forecasts have no more rain for southern California in the pipeline for the next few weeks.  Other predictions bring at least a couple more rain storms once we get into early February.  It's a tossup. 

If the storm-free forecasts win out,  things will dry out again and we'll be right back where we've been all month, with wildfires raging once again in and near Los Angeles and San Diego. 

The best bet for southern California is a series of light rain storms coming one after another, without torrential downpours. That's really threading the needle.

Given the weather extremes that California and so many other places have been going through lately, I unfortunately am not betting on the "Goldilocks" scenario of light rains. It will probably be either more drought or torrential downpours. 

 

California Fires Flare In High Winds, But So Far No New Calamities, We Hope. Expected Rain Brings Joy And Worry

Smoke from a wildfire rises perilously close to some
apartment buildings Tuesday in San Diego. Firefighters
were able to put a stop to the fire. One of the apartment
buildings suffered minor damage. 

 It looks like Southern California got through the latest round of strong, dry winds that could have caused more calamitous wildfires not exactly unscathed, but better than it could have been.  

At least so far. The risk is far fro over as new fires broke out Wednesday amid continued gusty winds and arid conditions. 

The dry, strong winds have picked up again today and continue a threat of fast moving wildfires through Thursday morning. 

Numerous brush fires broke out amid the high winds Monday and Tuesday, but they were largely contained because additional firefighters had been staged in the region. 

Firefighters managed to get the upper hand on those fires before they could do much damage.

A worrisome exception might be a fire that broke out this morning in Rancho Bernardo, California, a little northeast of San Diego. At least one person has already been injured in the blaze and evacuations are underway. 

Video shows that fire was burning near a densely populated area. However, latest word as of 2 p.m. EST is that the fire showed signs of being brought under control. 

Another worrisome wildfire just broke out a couple hours before this writing in Castaic, California, near Santa Clarita. It, unfortunately was spreading rapidly amid strong winds and hasty evacuations were ongoing. 

At least two other wildfires broke out in the San Diego area on Tuesday, including one near a shopping mall and a dense collection of apartment buildings on steep hills. Looked dire, but firefighters appear to have defeated that fire, too, It looks like this blaze spread into and damaged one of the apartment buildings.  It appears firefighters saved most of that building, and the damage appeared to be rather minor. 

Near Los Angeles one fire popped up along the 405 in Granada Hills. Another spread through more than 40 acres in Riverside County. An arsonist set a fire in Griffith Park, but crews stopped it before it covered an acre and an arrest was made. 

Southern Californians are looking forward to finally seeing some rain that's in the forecast for the upcoming weekend.

The rain is obviously mostly great news, as it would at least temporarily tamp down the fire threat.  

Overall forecast rainfall amounts aren't expected to be excessively heavy, But a pool of cold air aloft could set off thunderstorms with locally heavy rain. If one of those downpours moves over any steep slopes where one of those massive fires raged this month, you're set up for some horrible debris flows. 

Especially since the fires just barely happened so everything is especially unstable.  The fires also cooked the surface of the soil, making it hard and impermeable to rain.  So the water runs off and as that water rushes downhill, it picks up debris. Whoever is then at the bottom of that hill is thus in real trouble.

Even then, the fire risk isn't over. It looks like southern California will turn rainless again after this weekend and that dry weather should last into February.  

After California Fires Ease, More Homes Likely Will Be Destroyed In Mudslides

Devastation after a debris flow killed 23 people in 
Mendicito, California in January, 2018. A large wildfire
a month earlier set the stage for this disaster.
The same or worse could happen again in the '
aftermath of this month's wildfires if the
weather turns very wet in February and March. 

 In what might at first glance seem like a strange development, a Pacific Palisades house miraculously spared by this month's wildfires was destroyed by a mudslide on Wednesday.  

No, unfortunately,  it did not rain in southern California yesterday.

 Instead, the home above where the mudslide started was destroyed in the fire.  Firefighting efforts and water leaks caused by the blaze soaked the steep hill, causing the mudslide.

This brings about a bigger worry:  If the rains finally returns, southern California could face devastating mudslides. 

This is always a risk on and below hillsides in the few years in the aftermath of a wildfire.  Vegetation that hold soil and rocks in place has been destroyed.  

Also, the heat of the fire makes soils "hydrophobic."  Yes, kind of afraid of water. 

The wildfires create a layer on top of the soil that water can't penetrate. Burning vegetation forms a sort of wax that oozes into the soil, then hardens when it cools. That creates that "hydrophobic" layer that rainwater can't get through. 

Then, when it finally rains on steep slopes, the rain starts running downhill, gathering fire debris, rocks, stones and whatever else it can grab.  These turn into devastating debris flows that wipe out everything in their path.  

The problem can last months or even years after a fire, but the sooner it rains heavily after the wildfire, the more critical the risk. 

Which leads us to the California wildfires. 

It's supposed to be the rainy season right now in and around Los Angeles. That it hasn't really rained yet this winter is why this wildfire devastation was so surprising. Had it rained like it normally would have, there still would have been an awful windstorm with lots of trees and power lines toppled. But there would have been either no fires, or blazes that wouldn't spread much and be easy to suppress.

The rainy season in southern California goes into March.  It could suddenly turn very wet.  Especially in this age of climate change, there's a greater propensity for "weather whiplash," in which conditions go abruptly from hot to cold and back again, or very wet to super dry to soggy again. 

I'll have more on this intensified "weather whiplash" in an upcoming post.

There's no real sign of rain in southern California anytime soon. Los Angeles might go the entire month of January without seeing any rain at all. On average, L.A. usually gets a little under three inches of rain in January.

There are subtle signs the weather pattern could change toward something wetter in February, though nobody knows for sure. 

POST-FIRE DEBRIS FLOWS

A worse case scenario is if the things change so abruptly that atmospheric rivers start plowing into the southern California from the Pacific. Atmospheric rivers are narrow bands of deep moisture that can create torrential rains and flooding.  

Atmospheric rivers hit the Los Angeles area last February, dousing the city with ten inches of rain that month - with seven inches coming in just two days.  To nobody's surprise, that caused some horrible flooding and mudslides. and causing some serious flooding. 

If the same thing were to  happen this February, it would be catastrophic. Freshly burned hillsides would slip away or send intense debris flows flying down hillsides. Also, the wreckage of destroyed homes would not have been removed yet, so that would add to the scary debris flows.

These things hit fast, and there's little time to get out of their way.  Usually, there's less time to evacuate ahead of a debris flow  than people had when they fled this month's wildfires.

There's a history of devastating debris flows after wildfires, both in the L.A. area and elsewhere. 

On December 4, 2017, the Thomas Fire broke out and consumed 282,000 acres in Ventura and Santa Barbara counties and consumed 1,000 structures. At the time, it was the largest wildfire in California history. 

Later that winter, the usual winter rains arrived in southern California. On January 9, 2018,  torrential rain fell on the Thomas Fire burn scar and sent a huge, devastating debris flow through Montecito, California, killing 23 people, injuring 150 and leaving hundred of homes and businesses destroyed or damaged.   

Last June, wildfires raced through the hills above Ruidoso, New Mexico, a community of about 8,000 people. Then the normal monsoon thunderstorms hit later in the summer. At least eight times, debris flows from the fire area crashed through the city during and after those summer downpours. 

As of today, the fires still rage in southern California. More strong, dry winds are possible next week, which could make the situation worse. 

Everybody wants it to rain in southern California. But we had better hope and pray the wet weather comes in the form of weeks with long periods of drizzle, light rain and fog. Such gentle wet weather would minimize debris flows.

The worst case scenario would be thunderstorms and downpours, which would a southern California catastrophe so much worse.   

California Floods/Wind Much Worse Than The Usual Winter Storms Out There

Satellite photo this morning shows the massive 
storm plowing into California. Severe flooding 
and wind damage is likely out of this one, 

 As of this morning, California was just starting to endure perhaps the worst storm in years.

Practically the entire state is under the gun for either life-threatening flooding and mudslides, very damaging winds, and in the mountains, feet of snow. 

Winter storms and atmospheric rivers regularly smack into California, causing flooding, mudslides, wind damage and mountain blizzards. 

Most of the state is receiving heavy rain from this, but the worst of the downpours will probably hit southern California. 

"All systems are go for one of the most dramatic weather days in recent memory," the National Weather Service office in Los Angeles wrote in their Sunday morning forecast discussion. 

 NOAA's Weather Prediction Center has put large parts of southern California, including all of the Los Angeles basin and pretty much all the nearby mountains are under a high risk of flash floods.

That's a rare designation that only happens a handful of times a year anywhere in the nation. A high risk of flash floods designation is typically issued on only about 4 percent of the days out of the year. But high risk days yield 39 percent of all annual flood deaths and 83 percent of all annual flood damage in the U.S.

An example: Vermont was under a high risk flood designation this past July 10 and look what happened.

Lower elevations around Los Angeles were expecting three to six inches of rain with six to 12 inches in the foothills and mountains. 

This is way more than enough to trigger mud and rock slides and debris flows, especially near areas that had wildfires. Santa Barbara County is expected to get some of the heaviest rain, and several neighborhoods there were evacuated ahead of the storm because of the dangerous risk of debris flows.

The evacuations include parts of the ritzy small town of Montecito, where a 2018 mudslide killed 23 people and destroyed at least 100 homes. 

Although flooding is possible in central and northern California, the bigger risk there is high winds. Officials were anticipating many power outages, downed trees and some structural damage as winds gust over 60 mph. Stronger winds were forecast near the coast.

The first-ever Hurricane Force Wind Warning has been issued for the California coastal waters near Big Sur. 

The National Weather Service office in Sacramento had this forecast and advice for people in the Sierra Nevada range:

"For the Sierra, snow accumulations of 2 to 4 feet are expected, with up to 6 feet at the higher mountain peaks. Southerly winds gusting as high as 65 mph will be possible......Heavy mountain snow and strong, gusty winds are expected to bring difficult to impossible mountain travel with snow-covered roads, chain controls, road closures and whiteout conditions at times."

Considering the strength of the storm and the large population its hitting, I  have a feeling this storm will end up being yet another storm that causes at least $1 billion in damage. 

 By the way, longer range forecasts so far have this storm falling apart well before reaching Vermont. It might eventually produce clouds and perhaps a little light rain or snow next weekend. 

Of course, I'll  have more on this California storm as it develops. 

 

The Slamming Of California Begins

Residents who live near areas where wildfires burned last
year evacuate ahead of a soaking storm that promises 
to produce dangerous debris flows in fire zones.

 The well-advertised storm in California has arrived, and will be getting worse through the day. 

Already, strong winds have swept through central and northern parts of the state, with many felled trees and power lines in and around Sacramento, for instance. 

The real trouble with this winter storm in California is of course the rain and mountain snow. 

Even ahead of the storm, highways were closed and emergency managers ordered evacuations near areas where wildfires raged last year.  Some of these areas anticipate up to eight inches of rain over the next couple of days. 

The fires burned away trees and roots that hold soil and rocks in place, so they'll start sliding when the rain really hits. The Santa Cruz Mountains are a particular danger spot, and at least 5,000 people have been evacuated from that region. Some holdouts remain, refusing to leave, so we just have to hope they'll stay safe.

Ominously, the National Weather Service office in San Francisco early this morning detected rainfall rates as high as a half inch in 15 minutes, which could really set off the debris flows.  

To give you an idea of how bad it could get, we might look back at a debris flow in January 2018 that hit Montecito, California.  A large wildfire burned above the community the year prior.  Rainfall, similar  to intensity to what's going on in parts of California now, swept a massive mud and debris flow through neighborhoods in the middle of the night, killing 23 people. 

You can see why a lot of people in California are taking no chances with this one. 

On Tuesday, the National  Weather Service office in San Francisco put out a pointed warning in their forecast discussion as the threat of mud slides, debris flows and flooding grew, especially near where wildfires burned in 2020:

"This is the type of event that usually causes numerous rock and mudslides along Highway 1.  Residents of Big Sur should be prepared for extended periods of isolation."

Blizzards that will drop many feet of snow in the Sierra Nevada mountains are also signaling danger. 

The National Weather Service office in Reno was also in hair on fire mode Tuesday:

"Be where you need to be by sundown today (midnight at the absolute latest) -- you might be there for a couple of days. Have a backup plan for school/work/childcare/etc. Ground travel could become impossible at times tonight through Thursday, especially in the Sierra" 

Obviously, this storm isn't all bad. California needs the rain and snow, given the drought the state has experienced. This storm might be coming too hard, too fast, but at least it will help recharge ground water. It will add nicely to the Sierra Nevada snow pack, an important source of water for California when that snow melts in the summer. 

I surmise this is at least partly a symptom climate change. The atmospheric river and the strength of the storm hitting California are only moderately powerful. Big certainly, but they've seen worse. The problem is the widespread nature of last year's wildfires have turned what would have been a somewhat risky storm into one that packs real danger.

And I'm convinced last year's fires were made worse by climate change. And yes, I know poor forest management and increasing housing development in fire risk areas also play a big part in this. 

Stay tuned for more California storm news as the next couple days wear on. I'm sure there will be more drama out there. 

California Does A Flip Flop In New Stormy Pattern

Forecast amounts of 
rain and melted snow 
in California over the 
next 7 days could 
exceed a foot in some spots

That new, stormy pattern in the United States (except for here in Vermont!) is about to give some serious weather whiplash to California. 

The drought out there is severe - a symptom of it has been the weird January brush fires out there - but they're starting to get relief. 

Rain has been already starting to fall out there the past couple of days, and it looks like it will continue to do so off and on for the next couple of days. With snow in the mountains of course. 

Great! They can start chipping away at the drought and build up some winter snow pack for water usage in the summer. 

But then the fire hose starts.  Strong storms and an "atmospheric river" will dump enormous amounts of rain in parts of the state and even more enormous amounts of snow later this week. 

Although the following is probably an overestimate, one computer model dumps up to 30 FEET of snow -the equivalent of 23 inches of rain on the Sierra Nevada mountains in less than two weeks time. 

Lowland areas could get half a foot of rain just in the next seven days. 

In the grand scheme of things, this is mostly great. The past six months have been the driest, or nearly the driest on record in much of California. 

The problem is, some of this will be too much too fast, especially in areas that had those big wildfires. Torrential rains in these areas will create some dangerous debris and mud flows.

Remember, the fires eliminated brush and trees, whose roots normally hold soil and rocks in place.  Now, everything is loose, and can come crashing down on neighborhoods at the bottom of the hills. 

People could find their houses narrowly escaped last year's wildfires only to have them wrecked by mud and debris flows. 

While I'm reluctant to pin one weather event on climate change, this abrupt jump to drought to flooding is consistent with climate change on the West Coast.

Atmospheric rivers in the winter - those channels of super wet air that hit different parts of the West Coast during the winter - usually have more good consequences than bad.  They provide much of cold season rain and snow that sustains California during their bone dry summers. 

They can get out of hand, though. One such event in 1862 flooded most of California's Central Valley, including almost all of Sacramento.  

Climate scientists are saying that while intense droughts are becoming more frequent in California, the risk from atmospheric rivers is paradoxically rising 

A warmer world means the air can hold more moisture, so atmospheric rivers can become more intense, causing higher risks of flooding. 

Some studies suggest there could be a three fold increase in the type of 1862 mega-atmospheric rivers by the end of the century in California.

Now that California is our most populous state, an 1862 type flood would be catastrophic for the state, and the nation as as whole.  

Nobody is suggesting the deluge later this week will turn into anything like 1862.  For one thing, it won't last weeks, like 1862, so there won't be time for flood waters to accumulate. It'll taper off within a few days.

And as noted, there's a drought in California right now. There's plenty of room for excess water to drain, aside from the those debris flow-prone areas and urban areas, where street flooding is likely. 

I'm sure skiers will also rejoice in the incredible snows in the Sierra Nevada - once they manage to re-open the roads out there after the anticipated snowy deluge.