An exceptionally dry January-February is expected to set the stage for a challenging third year of drought along with another severe wildfire season.
A National Weather Service release Wednesday recapping the first five months of the water year in Northern California from Oct. 1 through Feb. 28 underscores the challenges ahead in the coming months.
Despite a record December that saw many areas receiving record rainfall or snowfall as much as 125 to 200 percent of the normal average for the month, large swaths of the critical Sierra and Cascades mountain ranges that California relies on the snowpack for 40 percent of its water remain in severe drought.
Almost all of northern and central California after the record January-February dry spell was at between 25 and 90 percent of the average precipitation for the first five months of the water year.
The exception was almost all of San Joaquin County along with a large segment of the Stanislaus River watershed that the South San Joaquin Irrigation District and by extension the cities of Manteca, Lathrop and Tracy rely on. The overall region was between 90 and 110 percent of normal from Oct. 1 through Feb. 28.
That was despite the Manteca-Stockton area receiving only a trace of rain in January-February while Modesto recorded 0.01 inches.
The driest back-to-back consecutive January and February on record in more than 100 years put a huge dent in December’s snowpack that was 160 percent of average.
As a result, the Department of Water Resources survey for March 1 revealed the snowpack was at 63 percent of normal for the date with the all-important water content projected at 66 percent of average.
And while the Climate Weather Prediction Center predicts better chances for more snow and rain in the Northern Sierra for the rest of March, there is low confidence that the Central and Southern Sierra will see that same benefit.
The Central Sierra snowpack supplies the Stanislaus, Tuolumne and Merced watersheds that the Northern San Joaquin Valley is dependent on for much of its farm and urban water needs.
Storage in the 2.4 million-acre-foot capacity New Melones Reservoir that plays a major role in water for the Oakdale Irrigation District plus the South San Joaquin Irrigation District that serves farms as well as the cities of Manteca, Lathrop, and Tracy, was at 1,455,585 acre feet or 67 percent of normal storage for March 10.
Don Pedro Reservoir with a 2 million-acre-foot capacity on the Tuolumne River that supplies the Modesto and Turlock irrigation districts was at 80 percent of average for March 10 with 1.498 million acre feet in storage.
The 1 million-acre-foot McClure Reservoir has 523,704 acre feet in storage or 56 percent of its average capacity for March 10.
SSJID anticipates with careful use of water even if March — the final month of the traditional wet season — will be OK for the balance of the water year that ends Sept. 30. That’s because modeling shows at least 600,000 acre feet of runoff is expected on the Stanislaus watershed even with the dismal outlook. That represents the water they have the legal rights to each year.
All of the Central Valley as well as the Central and Southern Sierra are in severe drought based on the United States Department Drought Monitor. There is no part of California that isn’t in drought.
It is why state water officials are imploring Californians to conserve water.
Statewide reservoir storage is at about 73% of average, and the largest reservoir, Lake Shasta, is only 37% full.
Snowmelt from the Sierra and other mountains normally provides about a third of the state's water supply.
Gov. Gavin Newsom has been calling for Californians to reduce water consumption by 15% from 2020 levels since last summer. California snowpack far below normal after dry winter months
There was some melt during warm February weather, but the bulk of the current snowpack should remain intact for several weeks.
Historically, December, January and February are California's wettest months, delivering over half of annual precipitation, and the snowpack reaches its peak on April 1.
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