Latest measurement shows Sierra snowpack well below average



The fourth snow survey conducted by the Department of Water Resources at the Phillips Station snow course on Thursday showed that the snowpack is way below average.

The manual survey showed 49.5 inches in snow depth and snow water equivalent, or how much water is contained in the snowpack showed 21 inches. These measurements are 83% average for that location, but that’s not the trend for the rest of California and Nevada.

The electronic snow survey stations showed that overall in California the snow water equivalent is 16.5 inches, which is 59% of average.

“With below average precipitation statewide, California’s reservoirs continue to show the impacts due to dry conditions,” said Sean DeGuzman, chief of DWR’s snow surveys and water supply forecasting section who conducted the survey.

(From left) Anthony Burdock, Water Resources Engineer, Snow Surveys and Water Supply Forecasting Section, California Department of Water Resources, and Sean de Guzman, DWR Chief of the Snow Survey and Water Supply Forecast Section, conduct a 2021 snow survey at Phillips Station in the Sierra Nevada Mountains on April 1. <em id="emphasis-36853acde6a3367e9f4b4f76437b2999">Provided / Florence Low of California Department of Water Resources</em>

DeGuzman said that the fourth annual survey is the most important of the year in terms of water content because the April 1 survey is typically when California’s snowpack is the deepest and has the highest SWE.

This SWE metric is key for the department’s water supply forecast for the state as the snowpack melts.

While this location shows the snowpack is well below normal, it shows improvement from the prior year.

The Northern and Central Sierra fared better this year in terms of snowpack due to most of the storms coming from North. The storms that did hit the region brought more snow than rain.

“This year’s hydrologic picture is somewhat contradictory in that the Northern and Central Sierra Nevada watersheds have actually built up a decent, albeit below average snowpack. However, statewide rainfall has been well below average,” said DeGuzman. “This is somewhat of an anomaly at this course”

For water year 2021, the snowpack in the Northern and Central Sierra peaked at 70% of average, but rain is below 50% of average, which ties the record for the third driest year on record. The Sierra snowpack accounts for 30% of California’s fresh water supply in an average year.

The Northern Sierra remains well below average for both rain and snow. The most evident locations of this is at Lake Oroville where water levels are 53% of average and Lake Shasta where levels are 65% of average. Lake Shasta is the state’s largest surface water reservoir.

The total amount of water expected to enter California’s reservoirs when the snowpack melts is projected to be just 58% of average and the states major reservoirs are storing just about half of their overall capacity.

Last year, snowmelt was roughly 60% of average.

DeGuzman says that the biggest unknowns at this point are how dry the soils are under the snowpack and how much water will absorb into those soils before running off into rivers and streams.

“The next few weeks are critical to watch how much of that snow melt will actually enter into our reservoirs,” he said.

The department urges Californians to continue to conserve water.

“Water conservation is always way of life,” said DeGuzman.

The fifth snowpack survey is tentatively set for April 29.

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