Snowpack 249 percent above normal in Southern Sierra
The numbers as far as the snowpack is concern, particularly locally, continue to rise, leading to continued speculation water allocations will also continue to rise.
The State Department of Water Resources, DWR, conducted its second snow survey of the season on Wednesday, February 1. Locally as of February 1 the snowpack in the Southern Sierra was 249 percent of normal.
The snowpack is also already 155 percent of normal in the Southern Sierra if this was April 1. Those numbers have continued to rise since the first snow survey was done at the beginning of January.
Farther north the snowpack was 203 percent above normal for February 1 and 128 percent above normal for April 1 in the Central Sierra and 171 percent above normal for February 1 and 106 percent above normal for April 1 in the Northern Sierra. For the statewide average those numbers came out to be 205 percent of normal for February 1 and 128 percent of normal for April 1.
Arguably more importantly the average snow water equivalent continues to rise. As of Wednesday the average snow water equivalent was 35.1 inches in the Southern Sierra, more than double what it was at the beginning of January.
It’s 34.6 inches in the Central Sierra and 30.7 inches in the Northern Sierra which works out to a statewide average of 33.7 inches.
The state has received the best of both worlds as colder temperatures have followed the January storms to keep the snow water content favorable. The snowpack and the average snow water equivalent are the two major factors used in determining water allocations.
The State Department of Water Resources initially announced a water allocation of five percent of normal before the storms but have since revised that significantly upward to 30 percent and it’s speculated that allocation will continue to rise.
That’s a good sign locally which depends mainly on the federal Central Valley Project for its water allocation. The CVP will announce its initial water allocation this month and it normally uses the state’s water allocation as a guide.
The manual survey at Phillips Station in the Lake Tahoe area recorded 85.5 inches of snow depth and a snow water equivalent of 33.5 inches, which is 193 percent of average on February 1. The snowpack received
a significant boost from one of the wettest threeweek periods on record in California, following the driest three-year period on record. California also experienced above average precipitation in December just months after one of the hottest heatwaves in state history in September.
“California has always experienced some degree of swings between wet and dry, but the past few months have demonstrated how much more extreme those swings are becoming,” said DWR Director Karla Nemeth. “California is preparing for more intense and dangerous climate swings by bolstering both drought and flood preparation. While today’s results are good news for water supplies, we know from experience how quickly snowpack can disappear if dry conditions return in the months ahead.”
The state’s average snow water equivalent results are currently outpacing the record 1982-83 season but DWR stated “periodic rain and snow over the next several months will be key to get the biggest water supply benefit from the state’s snowpack without posing additional flood risks.”
“Large snow totals like today are a welcome sight but also present new challenges for water managers as they walk the fine line between water supply and flood control,” said DWR’S Snow Surveys and Water Supply Forecasting Unit Manager Sean de Guzman. “As we move into the snowmelt season in the spring, water managers will work to manage flood risk and optimize the snowpack’s water supply benefits during peak demands in the summer.”
On average, the Sierra snowpack supplies about 30 percent of California’s water needs. DWR is currently conducting Airborne Snow Observatory, ASO, survey flights to collect more information on the snowpack accumulated by the powerful storms. Data from these flights, which use LIDAR and spectrometer technology to measure snowpack across broad swaths of key watersheds, will be used by DWR to get an accurate account of California’s snowpack and its water content and will increase the accuracy of water supply runoff forecasts.
The next snow survey is tentatively scheduled for March 1.