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.