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March Storms Needed To Build Sierra Snowpack
California reservoirs are 'stable' with help from above-average January precipitation, according to the U.S. Drought Monitor. But March is needed to build Sierra Nevada snowpack, counted on for water supply in the spring and summer.
"In northern and central California, after experiencing decent December and January precipitation and mountain snows, February (normally a wet month) was rather disappointing," says the update released March 3.
So far, the weekly report says reservoir storage is doing better than expected considering the dry February.
"Even with the subnormal February precipitation, reservoirs were mostly stable as there was some carryover from high January flows and low elevation February snowmelt that kept inflows from being exceptionally low," the report noted.
But the lack of snowfall has dropped the average snow water equivalent (SWE) in the Sierra Nevada.
"The Feb. 1 average snow water equivalent (SWE) for the northern, central, and southern Sierras (23, 22, and 17 inches) was 120, 117, and 105 percent of normal, respectively," says the update. "By March 1, the SWEs in all 3 basins were still the same as Feb. 1, but the percent of normal had declined to 89, 85, and 75 percent, respectively, as the SWEs should have increasing during February but instead remained static."
The report says the "peak SWEs in the Sierra normally occurs on April 1, so there is still March left to build the snowpack."
The National Weather Service Climate Prediction Center says early March looks favorable to bring above-average precipitation to California - and more snow to the Sierra.
El Niño has not brought the above-average precipitation expected in California, and, with the three wettest months of the winter bringing below-average snowpack in the Sierra Nevada, officials are hoping for a "March Miracle."
The Drought Monitor drought intensity levels are Abnormally Dry, Moderate, Severe, Extreme and Exceptional Drought.
There were some "minor changes" to the drought depiction last week in California. Moderate drought increased to 95 percent in the state and severe drought covers 82 percent of California.
There were no changes in the other intensity levels, with 99 percent of California abnormally dry, nearly 61 percent in extreme and 38 percent in exceptional drought.
In the Pacific Northwest, "moderate precipitation (2-4 inches) was limited to coastal Washington, parts of coastal Oregon, and the central Cascades," according to the report. "Lighter amounts fell on interior sections of Washington and Oregon and northwestern California."
"Elsewhere, with conditions better than a year ago, but nothing extraordinary about this week, status-quo was the story for Washington, Idaho, Nevada, and the rest of Oregon," the monitor noted.
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