Sierra snowpack is one of largest ever at 237% of average

SOUTH LAKE TAHOE, Calif. - There is a lot of snow in the Sierra and around Lake Tahoe, with a new record passe with each storm all winter long. Today, the California Department of Water Resources (DWR) had its monthly measurement of snow at Phillips Station, west of Lake Tahoe near Sierra-at-Tahoe as well as at other locations in California.

The state is now at 235 percent of average for this date, and 237 percent of normal for the year per the automated sensor network. The southern Sierra is smashing records and has had an even more epic snowfall and that region's snow water equivalent (SWE) is now at 300 percent of average - greater than any other year since they started measuring.

Sean de Guzman, manager of DWR's snow surveys and water supply forecasting unit led the fourth measurement of snow depth and SWE at Phillips Station. He said April is the most critical month for snow depth results, and on Monday he measured 126.5" of snow at that location with an SWE of 54". This is 221 percent of the average for April 1 at that location.

The snow water equivalent measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast. DWR’s electronic readings from 130 snow sensors placed throughout the state indicate the statewide snowpack’s snow water equivalent is 61.1 inches or 237 percent of average for this date.

Northern Sierra locations have an SWE of 192 percent of average since a majority of this winter's atmospheric rivers and storms hit the central and southern Sierra more often. This area is critical as it is where the state’s largest surface water reservoirs are located.

Today found the fourth-highest percentage of SWE in the Sierra in 82 years of measuring, following 1952, 1969, and 1983.

The Sierra snowpack is a frozen reservoir, letting water officials know what the summer will be like for needs downhill. April is critical to know what is in store. Water officials are now moving from a snowpack building mode to snowpack melting, watching closely what the spring runoff will bring.

De Guzman said they are expecting 422 percent of average snowmelt runoff for the Kern River watershed, one of the key areas they watch. He said Monday's measurement was a dramatic improvement over what they found one year ago...one patch of snow in a field of dirt.

The state has over 260 snowpack measurement locations, both manual and electronic, and that data plus what they evaluate from the air help DWR with decision-making going forward for the summer and fall.

This year’s April 1 result from the statewide snow sensor network is higher than any other reading since the snow sensor network was established in the mid-1980s. Before the network was established, the 1983 April 1 statewide summary from manual snow course measurements was 227 percent of average. The 1952 April 1 statewide summary for snow course measurements was 237 percent of average.

“This year’s severe storms and flooding is the latest example that California’s climate is becoming more extreme,” said DWR Director Karla Nemeth. “After the driest three years on record and devastating drought impacts to communities across the state, DWR has rapidly shifted to flood response and forecasting for the upcoming snowmelt. We have provided flood assistance to many communities who just a few months ago were facing severe drought impacts.”

“This year’s result will go down as one of the largest snowpack years on record in California,” said de Guzman. “While 1952’s snow course measurements showed a similar result, there were fewer snow courses at that time, making it difficult to compare to today’s results. Because additional snow courses were added over the years, it is difficult to compare results accurately across the decades with precision, but this year’s snowpack is definitely one of the biggest the state has seen since the 1950s.”

The size and distribution of this year’s snowpack is also posing severe flood risk to areas of the state, especially the Southern San Joaquin Valley. DWR’s State-Federal Flood Operations Center (FOC) is supporting emergency response in the Tulare Lake Basin and Lower San Joaquin River by providing flood fight specialists to support ongoing flood response activities and by providing longer-term advanced planning activities. The FOC and DWR’s Snow Surveys and Water Supply Forecasting Unit are helping local agencies plan for the spring snowmelt season by providing hydraulic and hydrologic modeling and snowmelt forecasts specific to the Tulare Lake Basin that are informed by DWR’s snowmelt forecasting tools, including Airborne Snow Observatory (ASO) surveys.

There will be another measurement at Phillip's Station on May 1 due to the amount of snow still in the Sierra.