Heavy rains and snowfall since late last year have freed half of California from drought, but low groundwater levels remain a persistent problem, US data show Drought Monitor Thursday.
the latest survey found that moderate or severe drought covers about 49% of the state, almost 17% of the state has no drought or a condition described as abnormally dry. The rest is abnormally dry.
“It’s clear that the amount of water that fell this year really made the drought worse,” said Daniel Swain, a climate scientist at the University of California, Los Angeles. “It’s not completely ended the drought but we’re in a very different place than we were a year ago.”
California’s latest drought begins in 2020 and there is no relief in sight heading into this winter.
Three months ago almost all of California is in drought, including at severe and exceptional levels. Water agencies that serve millions of people, agriculture and industry are told to expect only a fraction of the requested allocation.
The turnabout began a series of atmospheric rivers that battered the state from late December to mid-January, building a massive Sierra Nevada snowpack, causing flooding, downed trees and pounding the coast with heavy surf.
Water authorities started increasing allocation and, after several generally dry weeks, strong storms with arctic air returned in February, creating epic scenes of white-capped mountains while closing highways and ski resorts and buried communities in enough snow to collapse roofs.
The monitor shows three regions receiving the most benefit from more precipitation, including snowfall measured in feet rather than inches.
The central Sierra and foothills are now out of drought or abnormally dry conditions for the first time since January 2020, the monitor said. The central coast from Monterey Bay to Los Angeles County is currently drought-free, along with two counties on the far north coast.
“The rain improved California’s soil moisture and stream flow levels, while the snow increased the mountain snowpack to above normal levels,” the monitor said. “Most of California’s reservoirs have filled again with water levels near or above average, but ground water level remain low and may take months to recover.”
As of Thursday, the water content of the Sierra snowpack, which provides about a third of California’s water, was 170% of the historical average on April 1, when it usually peaks, according to the state Department of Water Resources. .
Department officials plan to conduct snow measurements in the Sierra on Friday and make a briefing on how the remaining month of California’s traditional snow season will affect the state’s water supply.
Swain said the snowpack may be the largest ever observed in parts of California. The outlook calls for a continued wet pattern, especially for the northern part of the state, and several feet of snow, he said.
“If we can get through the rest of the season with no more roof collapses or snowmelt floods it will be a boon,” Swain said.
The snowpack may face threats such as early heat waves or, as some models predict, a warm atmospheric river that could cause melting and flooding. Swain said California is expected to remain cool and the chance of an atmospheric river is low.
“I think the snowpack will last well into the summer to melt and … some shaded patches will still be there next fall,” he said.
While reservoirs are filling from alarmingly low levels, recovery has been uneven as shown by the state’s two largest water storage facilities. Lake Oroville, 65 miles (105 kilometers) north of Sacramento, is at 73% of capacity, 116% of average so far. Another 90 miles (145 kilometers) north, Lake Shasta is only 60% full, 84% of average so far.
Swain said he expects Shasta to get good flows during the snowmelt season because the snowpack there is slightly higher but not extraordinary.
The US Drought Monitor is a joint project of the National Drought Mitigation Center at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration and the US Department of Agriculture.
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