Saturday, February 13, 2016

California Rain And Snowfall Starting To Sputter, Which Isn't Good

This chart shows this year's California
 precipitation (in black) is near normal
so far, but well below the level of past El Ninos. 
This was supposed to be a winter that smashed, or at least badly dented California's epic multi-year drought.

El Nino would drive numerous storms into the West Coast, and the Sierra Nevada snowpack would be incredible, and reservoirs would fill to the brim under relentless rains.

So far, this winter has turned out to be "meh" in California.

It definitely is a lot better this winter than in recent ones. The Sierra Nevada snowpack is much, much deeper than last year.

Storms have brought inches upon inches of rain to California, especially the northern half.  But if you look deeply at the figures, the rainfall and snowfall is less than spectacular. Good, but not great.

In the Sierra Nevada, snow pack is a little below normal for this time of hear, not way above like hoped. Plus, not much snow is forecast for the next week. AND, temperatures are way above normal, so some of that snow pack is melting prematurely.

Frankly, winters rains have not been good at all in outhern California, which has missed out on many of the storms.

Worse, a hot ridge of high pressure has settled over California this week, and will hold firm for at least another week yet.

That means rain-bearing storms will be shunted away from California. Record heat is increasing evaporation of what water there is, and, as noted, eroding the  snowpack in the Sierra Nevada. You want the Sierra snowpack to remain intact as long as possible into the spring,  That way, melting snow in the summer would keep feeding thirsty reservoirs.

The current heat is pretty intense. It's been in the low 90s this past week in some southern California communities. Los Angeles this week endured three days in a row with record high temperatures.

This is weird for an El Nino year, for sure. Climate blogger Robert Scribbler speculates climate change is impacting the ability for El Ninos to deliver rain to the Southwest.

Writes Scribbler:

"Quite frankly, it's insane that we're still seeing these conditions during a monster El Nino. These droughts should be rolling back as the storm track intensifies and hurls severe weather at the U.S. West Coast. But that's no happening. At least not consistently.

Instead, we keep getting these extreme ridge patterns in the jet stream over western North America. We keep getting these very warm, very dry spells of weather during the wet season. And now we have California snowpack melting away in February of all times."

The big hot ridges of high pressure that Scribbler notes have repeatedly formed over the West Coast over the past month, echoes the entrenched pattern in 2012 through 2014 that kept California in its torrid drought for these recent years.
Southeern California precipiation so
far this year is a little on the low side of normal,
and WAY below that of previous big El Nino years.

Is something broken? Has climate change permanently reduced the amount of rain and snow that comes down on the American Southwest. It's possible, and we need to study this further.

Actually,people are studying it further.

In a recent paper, Andreas Prein, a postdoctoral researcher with the National Center for Atmospheric Research, looked at the 12 major weather patterns that typically affect the Southwest. Only three of those patterns tend to make it rain more there, says

This research is in contrast to other research, which looked at overall precipitation trends in the Southwest. That prior research also indicates a multi-decade drying trend in the Southwest.

Prein's research shows that the three wet weather patterns he put under scrutiny are becoming less frequent.

"Nowadays, the droughts are not the same as 30 years ago. They can be more intense and last longer than we would expect 30 years ago," quotes Prein as saying.

That raises the spectre of megadroughts - decades long dry spells.  With tens of millions of people living in southern California and the rest of the Southwest, that brings up some scary questions. Questions that affect us all. Not just some family in Encino or something.

How do we get the needed water to them if there really isn't any to be had? Who pays for the billions of dollars in fixes to get water to the Southwest, somehow? What about the national and worldwide economic disruption if commerce can't continue in the Southwest like it does now? What if there's a reverse "Grapes of Wrath?"

You know how people fled the Dust Bown in the Great Plains in the 1930s to escape drought? What if millions of people flee a drought-stricken California for somewhere else? That's quite an upheaval.

All this might or might not happen of course. And if it does, we're talking long range planning here. Not tomorrow. There won't be an economic or population crisis because of the drought in California this weekend. But it's something to think about.  Better than being caught with flat feet years or decades down the road.

By the same token, and this might seem contradictory, some scientists fear occasional mega storms in California, energized and empowered by global warming.

The apparently contradictory scenarios make sense, though. There's a potential future of increasing western drought, punctuated by an occasion rare but intense storm that causes flooding. Then the water runs off pretty quickly, and the drought resumes.

In the short term, meaning over the next few weeks,  there's still hope, of course. Late February and March could still prove incredibly wet. Some El Nino years save the bulk of California's precipitation for late winter. Maybe that will happen this year, too.

California better hope so. It's sunny and beautiful and very warm in California today. Sometimes gorgeous weather is a bad thing. California has had way too much nice weather for its own good.

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