Deadly Atmospheric Rivers Swamp West Coast From British Columbian To Oregon, Now Targeting California

As rain began in San Francisco
Saturday it was already chaos
A power blackout meant many
driverless Waymo taxis stalled 
in intersections because they
didn't know what to do with
traffic signals that weren't working. 

After trashing British Columbia, Washington, and eventually Oregon this month, atmospheric rivers continue to harass the West Coast, and now the main target has shifted to California. 

The storms have caused hundreds of millions of dollars in damage in the Pacific Northwest. The wind energy from these storms has spread further damage from Idaho to New England. 

By the time we're done with these storms after Christmas. the entire area from north of Vancouver, British Columbia to San Diego, California will have been soaked and flooded and blasted. . 

I think this has turned out to be the nation's latest disasters costing $1 billion or more. And the damage will keep adding up. 

Let's take stock of what has already happened, and what we're bracing for, moving north to south. 

BRITISH COLUMBIA

The storms this month have caused a lot of power outages and flooding in British Columbia. Hundred of thousands of people lost electricity as surges of powerful winds blew through on several occasions in mid-December.

Ironically, drought in recent years has made the storms more damaging in British Columbia. Trees are weakened and damaged from the drought, making them more likely to snap and blow over in storms. 

Flooding hit British Columbia's Fraser Valley, damaging hundreds of homes   The Noosack River, which crossed into British Columbia from Washington, caused much of the flooding. 

Chilliwack, British Columbia had about 15 inches of rain between December 9 and 15, causing plenty of flooding and some landslides around the city, which is not far north of the border with Washington State. 

Power has not yet been 100 percent restored in British Columbia and some roads and highways remain closed due to flooding, washouts and mudslides. 

WASHINGTON

The last big atmospheric river surge finished crashing through Washington this past Tuesday into Wednesday with another gush of downpours and an even bigger gush of wind, as we noted the other day. 

Since then, the downpours have mostly devolved into the usual Pacific Northwest drizzles and mountain snows. But the damage is done and new post-storm problems keep popping up. 

Continued light rain, with a few bursts of heavier rain, falling on already super-soaked soil, is seriously increasing the risk of landslides in western Washington State. 

Sharp slopes on coastal bluffs, steep hillsides, road cuts and recently burned wildfire areas are most at risk. There have been several landslides already this weekend, The threat should continue for several days. 

A large marina in Tacoma was badly wrecked by debris and wind. Multitudes of trees were washed into the harbor by flooding rivers. Then, high winds turned those floating trees into battering rams, destroying docks and boats. 

Rainfall has been pretty incredible in some areas right along the Pacific Coast and in higher elevations. Forks, Washington, a little inland from the Pacific Ocean in northwest Washington, has received 22.1 inches of rain so far this month. 

Rain during the atmospheric rivers reached high into the mountains, melting the snow that usually forms a thick blanket way up on those slopes.  The snow levels are now down to normal elevations, and the fluff is finally piling up in the Cascades.

OREGON

In Oregon, one person died when he drove around flood barriers and got caught in swift, deep floodwaters. Elsewhere in Oregon, a family of five was rescued from a pickup truck that got caught in swift water. 

In Tillamook County, five drivers had to be rescued from floodwaters, most of them after they drove around barricades. 

The Clackamas River rose 26 feet, flooding through homes and leaving yards littered with large trees and other debris. 

Landslides closed many roads in Oregon, including several near Mount Hood National Forest; along a section of the Columbia River Highway and in Oregon City.  

The rain in Oregon has tapered off some, but rivers are still flooding, even if they are gradually receding. Forecasts of daily rain coming up through the next week, will slow the Oregon recovery. 

CALIFORNIA

Next on the atmosphere river hit list is California.  

The first blast of atmospheric river downpours is hitting California from roughly the Bay Area north. Flooding is a good bet today and tomorrow in many areas of northern California, but areas near Placerville, Oroville and Paradise, in the Sierra Nevada foothills. These areas could get five to seven inches of rain in the next 24 hours. 

Heavy rain would continue in those same foothill areas tomorrow, making any flooding even worse.

Another surge of deep moisture off the Pacific will renew heavy rains in California, and those downpours will spread south.

By Tuesday night and Christmas Eve, rainfall rates through much of the L.A area, especially higher elevations, could reach to an inch per hour or more. This sets the stage for lots of mudslides and debris flows, especially in areas that saw wildfires in the past couple of years. 

Moisture content in the storm will be near record high levels, according to the National Weather Service office in Los Angeles. The flood watch for northern California is lasting a long time. It starts today, and goes into next Friday. 

 In less than a week, Los Angeles could receive more than five inches of rain. Normal rainfall for the entire month of December in L.A. is 2.3 inches. 

Snow levels will be high in the Sierra Nevada, so some places that usually get snow in the winter will see rain. Rain today is falling at elevations below 8,800 feet, and the snow level should slowly drop to 7,400 feet, give or take, by Tuesday night  

Way, way up there in the high Sierra, accumulations this week will range from four to ten feet, or even more.

It's going to be a long, long, tedious Christmas week for California.   

Saturday Vermont Update: Big, Gusty Storm Over; But It Will Stay Windy And Changeable

Tree and wires down on Stone House Road in Enosburg
yesterday. Photo by Christopher Bergeron via Facebook

The weather was certainly all over the place on Friday, with those howling winds, record highs, drenching downpours, then crashing temperatures. 

See last night's post for a complete rundown of record highs and top wind speeds across Vermont. 

We won't have anything quite that extreme for awhile. But it's going to stay windy with more yo-yo temperatures for the next several days. 

Before we get into that, a couple more aspects of that wild storm we had yesterday. We here in New England were actually the victim of an atmospheric river, much like what hit the Pacific Northwest last week. 

Atmospheric rivers are long, narrow regions in the atmosphere, basically rivers in the sky, that transport enormous amounts of water from the tropics. The average atmosphere river carries an amount of water vapor equivalent to the average flow of water at the mouth of the Mississippi River, according to NOAA. 

The difference is, yesterday's atmospheric river targeted us only for a very short period of time. The Pacific Northwest event was a fire hose aimed at the same spot for weeks. 

Our atmospheric river, which originated in the Gulf of Mexico, was a lot like a firefighter sweeping his hose across a long, burning wall. We only got soaked for a few hours. 

But you can tell how strong these wet tropical fire hoses are.  We had those record highs, statewide, including that 63 degrees in Burlington. It was also Burlington's wettest December 19 on record, with 0.84 inches. Virtually all that rain fell in just five hours. 

Atmospheric rivers, working in tandem with storm systems. more often than not cause strong, often damaging winds. Which is what we saw in Vermont Saturday. 

Yesterday's atmospheric river didn't last long enough to cause any flooding. But they can cause havoc in New England, and they have. Our huge, catastrophic flood in July, 2023 was caused by an atmospheric river. 

According to reporting by Inside Climate News, researchers have concluded that atmospheric rivers along in the eastern United States  are increasing in frequency, while those on West Coast are decreasing, this month's weather notwithstanding. 

Between 1980 and 2020, eastern atmospheric river activity from the Gulf of Mexico and Atlantic Ocean increased at a rate of five percent per decade, according to the research.  Most of those atmospheric rivers affected the southeastern U.S, but some of them do make it up into the Northeast. 

One caveat: The distinction is a little dim between an atmospheric river and just blobs of deep moisture coming off the Gulf  and Atlantic. But this atmospheric river situation is a climate change signal that we ought to keep an eye on. It could be helping grow the propensity for extremes in the Northeast, including here in Vermont. 

LOOKING AHEAD

Over the next few days atmospheric rivers will be back to tormenting the West Coast. More on that on an  upcoming, separate post. 

There's no immediate sign of another atmospheric river for us anytime soon. But a fast coast-to-coast jet stream across the northern United States will ensure constantly changing weather here in Vermont, and a more windy days and nights.. 

Luckily, I don't see signs of winds getting as strong as they did yesterday. 

As of 9:45 a.m. today, there were still about 2,800 Vermont customers without electricity. A second big push of wind overnight kept creating new outages even as crews fixed problems created during the day Friday. Other damage included a building in downtown Winooski, where winds blew off a large section of brick veneer from the structure. 

The wind has died down, and the sun is out, so we're getting a Saturday break from all the noise outdoors. But it's a short break. Especially in the Champlain Valley. 

Another storm passing well to our north will pull in some stiff southerly winds over the Champlain Valley tonight. We won't get much precipitation out of it, maybe a few snow showers tomorrow morning. 

The storm will create strange temperature trends again, only this time it won't be extreme. Temperatures will slowly rise into the low 30s overnight instead of falling like they usually do. And during the day Sunday, temperatures will fall in the late morning and afternoon instead of rising like they're supposed to. 

For those of you who have no snow left on the ground after yesterday's storm, there's still one last chance of a white Christmas. 

It looks like another storm diving southeastward from the Great Lakes will cross New England Tuesday, laying down a stripe of snow across the region. Not much. Early guesses put us in the two to four inch range. And there's a possibility it could get warm enough for the snow to mix with rain. 

We'll get updates as we get closer to the event. 

Beyond Tuesday, it gets even harder to predict what will happen. With such a fast west to east flow in the atmosphere, it can get tricky to tease out when each disturbance will come through, how strong they might be, and whether enough warm air will come in to mix in some rain or ice with the snow chances. 

The weather pattern will mean more spells of gusty winds, so hang on to your Santa hat. 

Meteorologists, and probably everyone else will need to stay on their weather toes Christmas week. But I don't see any signs of another big storm anytime soon. 

Greenland Atmospheric River Temporarily Slowed The Island's Inexorable Ice Cap Meltdown

A massive atmospheric river hit Greenland in March, 2022
and dumped so much snow that it temporarily  halted
the dangerous melting of its massive ice cap. 

As land-based glaciers melt and wilt under pressure from climate change, sea levels keep rising as a result . Long term, it's easily one of the biggest threats to us humans as the world warms. 

That's one of the reasons why climate scientists are obsessed with Greenland. There's a lot of ice up there, and the more it melts, the more the sea levels rise. 

 If all of Greenland's ice mass melts, which I admit won't happen anytime soon, global sea levels would rise by an average of 23 feet. 

Which would be absolutely devastating. Even a couple feet of rising seas would be a zillion dollar, life threatening, world-changing  mess. So you see why Greenland is important.

It's mostly bad news as big bits and pieces of Greenland's ice melts every year in the stew of a climate change summer  Because they are human, scientists do look for, ore at least vaguely celebrate, any piece of good news. 

They found one of those happy pieces of news in a massive atmospheric river that hit Greenland in 2022. 

I've told you about atmospheric rivers in past posts.  Those are those ribbons of high moisture air that come off oceans, hit land and dump often incredible amounts of rain or snow over a relatively narrow area.

In one sense, they're good, as they supply a lot of the needed moisture that the West Coast of the U.S. and other place need. But they're very often bad, causing intense flooding. 

The atmospheric river that scientist seized upon from 2022 turned out to be a good thing. 

Per Gizmodo:

"A research pair has investigated the recent impact of an intense atmospheric river - a channel of water vapor that brings moisture and heat from warmer oceans to colder regions - on Greenland's ice sheet. 

Unexpectedly, they found that this phenomenon deposit 16 billion tons of snow on Greenland, thought to temporarily slow its ice melt. As detailed in a study published March 3 in the journal Geophysical Research Letters, atmospheric rivers might have a more positive impact than researchers had theorized.."

A positive impact, sure. But certainly not a cure-all.

The uber-snowy atmospheric rive that struck Greenland in March, 2022 slowed the island's yearly ice melt but didn't stop it. 

The Greenland ice sheet ultimately shrunk in 2022, just as it did for the previous 26 years and just as it did for the subsequent two.

But at least for now, atmospheric rivers might not always be the ice destruction events in Greenland scientists feared.  

The March, 2022 event suggests that Greenlandic atmospheric rivers could be snowy. Very, very snow. That buys just a bit of time in the Greenland ice melt derby. After all, the amount of snow that hit Greenland in that 2022 event boggles the mind. 

THE STORM

That same atmospheric river pummeled Svalbard, an island in the Arctic north of Norway with intense , highly unseasonable rain. 

Researchers who took samples and ice core readings after that epic atmospheric river found some surprising results in Greenland, as Gizmodo tells us:

"The ice core section revealed that the atmospheric river had brought 16 billion tons of snow to Greenland, single-handedly offsetting the ice sheet's yearly loss by 8 percent in just three days." An additional 4.5 billon tons of snow fell over the next few days as the atmospheric river slowly waned. 

Spring, 2022 in Greenland was otherwise unusually warm, so the atmospheric river prevented a LOT of potential ice melt. 

There's no guarantee, of course, that atmospheric rivers will bring welcome snow blitzes to Greenland. As the world continued to warm, a future March 22 mega snow could end up being a mega-rain.

Inches and inches and feet of rain on the Greenland ice cap would really set off a wave of melting that would dwarf any of the big melts we've seen up there in recent summers.