Low pack: California, Nevada facing critically dry years
Special to the Sierra Sun
Unless a series of storms blankets the Sierra Nevada with snow, California and Nevada are facing critically dry years.
Powder days have been few and far between this winter and that’s due to a snowpack that is well below average and five consecutive months of less than average precipitation.
The California Department of Water Resources manually measured the snowpack on a sunny Tuesday morning at Phillips Station, near Sierra-at-Tahoe, and it showed anomalous results.
The measurement showed the snowpack is 86% of average for the location and the snow water equivalent is 21 inches (83%), but California’s overall numbers are much less, at 61% of the March 2 average and is 54% of the April 1 average. Officials said April 1 is typically when California’s snowpack is the deepest and has the highest snow water equivalent. The SWE measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast.
“As California closes out the fifth consecutive dry month of our water year, absent a series of strong storms in March or April we are going to end with a critically dry year on the heels of last year’s dry conditions,” said DWR Director Karla Nemeth. “With back-to-back dry years, water efficiency and drought preparedness are more important than ever for communities, agriculture and the environment.”
With below-average precipitation across the state, California’s reservoirs are showing the impacts of a second consecutive dry year. Lake Oroville is currently at 55% of average and Lake Shasta, California’s largest surface reservoir, is at 68% of average. Lake Tahoe is more than 2 feet under what it was last year at this time and 3 feet under what it was in 2019 and is not likely to fill this year, officials said.
“This year has been similar to the water year 2014, which was the third year of California’s most recent severe drought, which lasted from 2012 to 2016,” said Sean de Guzman, DWR’s chief of snow surveys and water supply forecasting, said in a webcast from the Sierra site.
De Guzman noted that during that drought, 2014 and 2015 were California’s warmest two years on record and that the calendar year of 2020 was the third warmest.
“Although we can’t predict how much precipitation California will receive for the remainder of the year, without any series of storms on the horizon it’s safe to say that we’ll end this year dry so it’s important that we’ll have to plan accordingly,” he said.
State water leaders are preparing to address the current dry conditions using lessons learned during previous droughts, said a press release.
The State Water Project allocation of 10% amounts to 422,848 acre-feet of water, distributed among the 29 long-term contractors who serve more than 27 million Californians and 750,000 acres of farmland. Last year the initial allocation was also 10%, with a final allocation of 20% set in May 2020.
Precipitation in the form of rain — and snowfall at higher elevations — is critical because it refills reservoirs, packs away snow for spring runoff and helps stem the risk of wildfires.
“As dry conditions continue to persist, Californians should look at ways to reduce water use at home,” the release said. “Each individual act of increasing water efficiency can make a difference.
Conditions on the Nevada side are no better. The Nevada Natural Resources Conservation Service conducted a snowpack survey on Monday, March 1 that should equally bleak results.
At the Mt. Rose SNOTEL site, the snow was 68 inches deep with 21.1 inches of water content, which is 65% of median for this time of year.
Since Feb 1, only 3 inches of water content was added to the snowpack, a normal increase is 9 inches.
“An additional 16 inches of water content is needed to reach the median peak amount of 32.6 inches,” said a press release from NRCS. “Today’s measurement ranks 15th lowest in the last 41 years (since 1981).”
Measurements in Tahoe, Carson, Walker and Truckee Basins all show below average water content. According to the release, there is a 10-20% chance the snowpack will recover by April 1.
The Tahoe Basin needs a Miracle March, and it has started with a week of sun. According to the release, in 1991, March started at 26% below average and ended at 71% of average. Last year, March 1 started at 46% of average and ended on April 7 at 72% of median.
“February brought snow to eastern Nevada,” the release said. “The Ruby Mountains and Upper Humboldt River Basin picked up significant snow during the middle of the month. Snow in the Upper Humboldt basin increased from 65% on Feb. 1 to 89% on March 1. February precipitation in the Upper Humboldt basin was 164% of average.”
Still, NRCS is preparing for drought conditions and the Nevada Division of Water Resources is measuring the state’s well levels throughout the month of March. Lake Tahoe and Lahontan Reservoir are not likely to fill this year.
The NRCS press release stated since Oct. 1, 2019 precipitation is half a water year behind average.
“The lack of rains last fall has left soils under the snow at near to record dry levels for this time of year,” said the release. “In the spring, snowmelt will need to fill the soil profile which could lead to less runoff.”
Laney Griffo is a reporter for the Tahoe Daily Tribune, a sister publiation of the Sierra Sun.
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