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.