Thursday, March 6, 2014

recent storm 'no drought buster'

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Storms last week and through the past weekend brought badly needed rain and snow to California but they did little to affect the ongoing statewide drought, climatologists at the National Drought Mitigation Center and Caltech's NASA Jet Propulsion Lab in La CaƱada said in phone interviews.

"The big picture for California is the rain is welcome, but realistically the drought did not change from that one single precipitation event," Bill Fuchs with the U.S. Drought Monitor said Thursday March 6. "It brought some relief but it did not do a whole lot to change the overall situation."

The National Drought Mitigation Center is a federal partnership that includes the University of Nebraska, NOAA and the USDA. The drought in California is long-term and the recent rains were not enough to make a significant difference, Bill Patzert at JPL said.

"We had improvement," Patzert said. "Los Angeles was 10 percent of normal and now it's around 49 percent. So does that put a dent in the drought? Statistically speaking it did. But the reality is when you get that much water that rapidly it's like somebody shooting a fire hose and trying to catch it in a champagne glass.

"We've engineered So Cal 80 so that 90 percent of that rain water ends up in the ocean," Patzert said. "Statistically it looked like we went from 10 to 50 percent of normal but it came so fast we didn't catch it. We're not engineered to catch it, we're engineered to move the water to the ocean because we concrete lined all the rivers."

Here's a rundown of the storm from the National Drought Mitigation Center published March 6:

A blockbuster storm struck California as the calendar turned from February to March, averting a record-breaking season for dryness. From February 26 – March 2, the potent storm - and a weaker, initial system - accounted for more than 75 percent of the season-to-date precipitation in California locations such as Burbank (4.78 of 5.28 inches); downtown Los Angeles (4.52 of 5.72 inches); Camarillo (3.66 of 4.85 inches); and Sandberg (3.04 of 3.93 inches). However, after the precipitation ended, season-to-date (July 1 – March 4) totals were just 40 percent of normal in Burbank, Camarillo, and Sandberg, and 49 percent of normal in downtown Los Angeles.

At the height of the second storm, on February 28, Los Angeles - with 2.24 inches - experienced its wettest day since March 20, 2011. Los Angeles also received at least an inch of rain on 3 consecutive days (February 27 – March 1) for the first time since December 18-20, 2010. Benefits from the storms extended northward along the California coast and into some northern areas of the state, leading to a modest reduction in the coverage of extreme to exceptional drought (D3 to D4). However, short-term benefits from the storms were mostly offset by still-large, 3-year precipitation deficits, low reservoir levels, and a sub-par snowpack.

The California Department of Water Sources reported a slight jump in the water equivalency of the high-elevation Sierra Nevada snowpack. The water content, which averaged just 5 inches (22 percent of the late-February normal) prior to the two storms, climbed to 8 inches (33 percent) by March 5. The snowfall was heaviest in the southern Sierra Nevada, where a slight reduction in the coverage of extreme to exceptional drought (D3 to D4) resulted.

Storm water, mud and debris behind San Gabriel Dam: March 4 2014

The drought over the past 15 years has waxed and waned since 1999, Patzert said. During the past 30 years the demand for water has dramatically increased, for agriculture, new housing, suburban uses, and at the same time the population of California has quadrupled.

"Demand is up and over the last 15 years the supply is down," Patzert said. "You get a big storm and Mother Nature gets your hopes up but then it doesn't rain for another five or six months. Maybe we get another five years of this. If you look at the history of California it's written in droughts and they tend to be long. There's no quick fix for a drought.

"Everybody started hyperventilating about this storm last week," Patzert said. "It wasn't record breaking. This was an average storm. We hadn't seen one in such a long time, but it's no drought buster."

For background see:

How Dry was 2013? Cities of Riverside and L.A. Had Driest Calendar Years on Record

Photo by Guy McCarthy


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