Tag Archive for: Sierra Nevada snowpack

Precipitation-Snowpack Survey-Sierra Nevada-DWR

Precipitation Below Average in California

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Precipitation is below average in California for the current water year. Despite recent storms that increased the statewide Sierra Nevada snowpack to 70% of average to date, the state is experiencing its second consecutive below average year for rain and snow. The water year starts on October 1 and ends September 30.

The Department of Water Resources Feb. 3 conducted the second manual snow survey of the season at Phillips Station. The manual survey recorded 63 inches of snow depth and a snow water equivalent, or SWE, of 17 inches, which is 93% of average for that location, according to the DWR. The SWE measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast.

“The recent blast of winter weather was a welcome sight, but it was not enough to offset this winter’s dry start,” said DWR Director Karla Nemeth. “While there is still a chance we will see additional storms in the coming weeks, the Department and other state agencies are preparing for the potential for a second consecutive year of dry conditions.”

La Niña-Sierra Nevada-snowpack-climate-snow survey

Below normal precipitation is favored throughout most of the southern tier of the United States in late February to early March, according to the National Weather Service Climate Prediction Center. La Niña conditions remain over the Pacific Ocean.

Precipitation below normal

Statewide snow survey measurements reflect those dry conditions. Measurements from DWR’s electronic snow survey stations indicate that statewide the snowpack’s SWE is 12.5 inches, or 70% of the February 3 average, and 45% of the April 1 average. April 1 is typically when California’s snowpack is the deepest and has the highest SWE.

“The recent atmospheric storms have brought rain and snow to the northern Sierra Nevada, but conditions are still well below normal,” said Goldy Herbon, San Diego County Water Authority senior resources specialist.

Following last year’s below average water year, northern California is now experiencing its second straight water year of below average precipitation.

Colorado River Basin

Another source of the state’s water supply, the Colorado River Basin, isn’t faring much better. The water year 2021 precipitation at the end of January for the Colorado River Basin is 66% of normal, according to the U.S. Bureau of Reclamation.

Precipitation totals to date are behind historical averages for two of the main sources of San Diego County’s supply, with two months to go in the winter season but, a couple of atmospheric rivers can change that quickly.

“The San Diego region will have a plentiful and reliable source of water due to actions taken by the Water Authority and its 24 member agencies to diversify the water supply,” said Herbon. “Continuing efforts to expand supply sources, including desalination, water reuse, and recycling, will ensure that the water needs are met for the region’s 3.3 million people and its $245 billion economy.”

Fall 2020 was extremely dry, especially in the Sierra Nevada, and follows last year’s below-average snow and precipitation, according to the DWR. With only a couple months remaining in California’s traditional wet season, DWR officials say Californians should look at ways to reduce water use at home.

snowpack-reservoirs-Snow survey

Statewide Sierra Nevada snowpack is 71% of average for February 4, 2021. Graphic: California Department of Water Resources

Sierra Snow Grows, but Bay Area has 3rd Biggest Rainfall Deficit Since 1849

/in , /by /The Mercury Newsby Paul Rogers

California’s water picture is heading in two different directions.

A major storm last week and a more modest system Tuesday continued to boost the Sierra Nevada snowpack, the source of one-third of the state’s water supply, in promising ways. But the Bay Area and most cities across Northern California remain stuck in one of the worst two-year rainfall deficits seen since the 1849 Gold Rush, increasing the risk of water restrictions and dry wildfire conditions locally next summer.

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First Snow Survey of the 2020-21 Season Coming December 30

/in , , /by /ABC10 Sacramentoby Monica Woods

California’s first snow survey of the 2020-21 season is happening Dec. 30 at the Phillips snow course in the Sierra Nevada.

The Department of Water Resources will conduct five of these surveys through May by plunging a long steel tube into the snow. This will measure the snow’s depth and give an estimate of its water content.

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Water Supply Diversification Overcomes Dry Winter

/in , , /by /Water News Networkby Ed Joyce

No ‘March Miracle’ for snow and rain in California, but the San Diego County Water Authority has diversified water supply sources to weather the boom-and-bust cycle of California winters.

March brought abundant precipitation throughout California, but not enough to offset a dry February. Most large urban water agencies in the state maintain a reliable water supply in wet and dry years.

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Anza-Borrego Desert Research Center-Sicco Rood-March-2020-WNN water supply

Water Supply Diversification Overcomes Dry Winter

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No ‘March Miracle’ for snow and rain in California, but the San Diego County Water Authority has diversified water supply sources to weather the boom-and-bust cycle of California winters.

March brought abundant precipitation throughout California, but not enough to offset a dry February. Most large urban water agencies in the state maintain a reliable water supply in wet and dry years.

“California’s climate variability is why a water resilience portfolio is needed to provide a safe and plentiful water supply,” said Goldy Herbon, Water Authority senior water resources specialist. “Whether a wet or dry year, the Water Authority and its 24 member agencies have successfully diversified water sources to ensure a reliable supply to meet the needs of the region’s 3.3 million people.”

The supply sources include water from the Claude “Bud” Lewis Carlsbad Desalination Plant, where ten workers volunteered to live on-site to keep the water flowing during the coronavirus pandemic.

Lindbergh Field has received 9.76 inches of rain – or 108% of normal – from October 1, 2019 – April 2, 2020. Many areas in the San Diego region received snow in March, including the Anza-Borrego Desert State Park.

Even with a lackluster winter, the state’s six largest reservoirs hold between 82% and 125% of their historical averages for April 1, according to the California Department of Water Resources. Lake Shasta is 98% of its historical average and is at 79% of capacity.

Major California Reservoirs-April 1 2020-WNN-CA DWR graphic

The Department of Water Resources April 1 conducted the fourth manual snow survey of 2020 at Phillips Station near Lake Tahoe. The manual survey recorded 43.5 inches of snow depth and a snow water equivalent (SWE) of 16.5 inches, which is 66% of the April average for this location.

The SWE measures the amount of water contained in the snowpack, which provides a more accurate forecast of spring runoff. Measurements from the 130 electronic snow sensors, scattered throughout the state, indicate that the statewide snowpack’s water equivalent is 15.2 inches, or 53% of the April average.

Sierra Nevada Snowpack Comparison-NASA satellite image-WNN-April 2020

The natural-color satellite images above, acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites, show the area covered by snow in March 2020 compared to March 2017 (a record high year). Graphic: NASA/NASA JPL

“While today’s survey results show our snowpack is better off than it was just last month, they still underscore the need for widespread, wise use of our water supplies,” said DWR Director Karla Nemeth. “California’s climate continues to show extreme unpredictability, and February’s record dryness is a clear example of the extremes associated with climate change.”

On average, the snowpack supplies about 30% of California’s water needs as it melts in the spring and early summer, the state agency reported in news release.

Early April Precipitation is Expected to be Below Normal Where it is Most Needed in Northern California

/in , , /by /Los Angeles Timesby Paul Duginski

April showers may be more scarce than normal north of Point Conception in California, according to an outlook produced by the National Oceanic and Atmospheric Administration.

This area where the probability of precipitation is below normal includes virtually all of Northern California and the crucial northern Sierra Nevada, where the state’s largest reservoirs are located.

While snow cover has increased thanks to a series of March storms, the Northern Sierra 8-Station Index stands at 56% of normal for the season. As of March 24, another 29.25 inches would be needed to reach the season normal of 54.52 inches.

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California Mountains Blanketed in Snow After March Storms

/in , , /by /Associated Press (Sacramento Bee)by John Antczak

California mountains are blanketed in snow and much of the state has had plenty of rain in a remarkable March turnabout from the extremely dry first two months of the year.

The most recent statewide storm started during the weekend and, despite diminishing, snow snowfall and showers were still occurring here and there.

In the Sierra Nevada, Homewood Mountain Resort on the west shore of Lake Tahoe reported late Tuesday a storm total of 114 inches (289.5 centimeters) of snow at its summit and 74 inches (188 centimeters) at the base.

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Winter Storm a Massive Boost for Sierra Snowpack

/in , , /by /Tahoe Daily Tribuneby Bill Rozak

One storm does not make a “Miracle March” but what an impact the last few days have had on the Sierra snowpack.

Continuous snow at Lake Tahoe since Saturday morning has added 13% to the snowpack, according to Jeff Anderson, water supply specialist for the Natural Resources Conservation Service in Nevada.

“To gain back that amount this time of year is really hard,” Anderson told the Tribune.

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Sierra Nevada Snowpack Feb 27 2020 California DWR-WNN

California’s Winter: Wet Times, Dry Times and Water Supplies

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After a wet and snowy start, California’s winter has gone bust. The 2019-2020 water year started off with robust precipitation after a series of storms in November and early December 2019.

But the new year has not been as bountiful. Dry conditions in January and February added little to the Sierra Nevada snowpack.

NASA-NWS-Sierra Snowpack Comparison - Water News Network Feb 2020

Left: 2019, Right: 2020. Sierra Nevada snowpack is below normal for this time of year, at about 58% statewide. Graphic: NASA/National Weather Service via NWS Sacramento

Drought-resilient water supplies through diversification

Due to California’s climatological variability, including periods of drought, the Water Authority and its 24 member agencies have diversified water supply sources. Those successful efforts ensure supply reliability for the region’s 3.3 million residents and its $245 billion regional economy.

“Based on current supply levels, the Water Authority and its 24 member agencies will meet anticipated demands through a combination of drought-resilient local and regional water resources,” said Goldy Herbon, Water Authority senior water resources specialist.

Water supplies will meet demand

Herbon said the Claude “Bud” Lewis Carlsbad Desalination Plant, conserved agricultural water transfers, savings from canal lining projects and continued water-use efficiency measures are among the reasons the region’s water supply will meet demand.

The multi-decade water supply diversification plan, along with major infrastructure improvements and forward-thinking policies, also promote fiscal and environmental responsibility.

“A comparison of the snowpack across the Sierra-Cascade range over the past 6 years shows the true variability of a California wet season. While numbers are similar to the 2017-2018 winter, snow did extend into somewhat lower elevations back then.” NWS Sacramento, February 26, 2020

Dry times in Northern California

While rainfall totals have been closer to average in most of Northern California, downtown Sacramento and downtown San Francisco did not receive any precipitation in February, according to the National Weather Service. The last time San Francisco saw a dry February was in 1864, according to the NWS.

NWS Sacramento Dry February 2020

Rainfall above historical average in San Diego

Southern California is faring better, with rainfall at 125% of the historical average at Lindbergh Field in San Diego.

Most major California reservoirs are at or above the historical averages for late-February.

The state’s largest six reservoirs currently hold between 92% (Oroville) and 132% (Melones) of their historical averages for February 26. Lake Shasta, California’s largest surface reservoir, is 107% of its historical average and sits at 78% of capacity, according to the California Department of Water Resources.

Water Supply-Major Reservoirs-DWR-WNN Feb 2020

California’s largest six reservoirs hold between 92% and 132% of their historical averages for Feb. 27. Lake Shasta, California’s largest surface reservoir, is at 107% of its historical average and is at 78% of capacity. Graphic: California Department of Water Resources

The Department of Water Resources February 27 conducted the third manual snow survey of 2020 at Phillips Station. The manual survey recorded 29 inches of snow depth and a snow water equivalent of 11.5 inches, which is 47% of the March average for this location, according to a DWR news release. The snow water equivalent measures the amount of water contained in the snowpack, which provides a more accurate forecast of spring runoff.

Spring storms could boost snowpack

“Right now, 2020 is on track to be a below-average year but we could still see large storms in March and April that will improve the current snowpack,” said Sean de Guzman, chief of DWR’s Snow Surveys and Water Supply Forecasting Section. “While periods of dry conditions are expected in California, climate change has made them more unpredictable and extreme which is why we must always use the water we have wisely.”

March April May precipitation 20-Feb-2020 NWS CPC

The seasonal outlook for March, April, and May sees below-normal chances for a wet period across California and the Southwest U.S. while most areas are favored to be warmer than usual. Graphic: National Weather Service Climate Prediction Center

Looking ahead, the National Weather Service Climate Prediction Center forecast favors above-normal temperatures and below-normal precipitation through May for most of California.

NWS CPC Spring 2020 temperature forecast-WNN

The National Weather Service Climate Prediction Center forecast favors above-normal temperatures and below normal precipitation through May for most of California. Graphic: National Weather Service Climate Prediction Center

Opinion: Climate Change and Water Supply

/in , /by /CalMatters (Sacramento, Calif.)by Dan Walters

California, as everyone knows, receives virtually all of its precipitation during a few fall and winter months and in 2019, some early rain and snow storms promised a bountiful water year.

This year, Mother Nature kept that promise in Southern California, where precipitation is running at or above the normal, but Northern California — far more important from a water supply standpoint — has been a different story.

The north has seen almost no precipitation since Christmas, the all-important Sierra snowpack is less than half of its average depth, and the region’s balmy, springlike weather shows no signs of ending.

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