San Francisco Chronicle
Snowpack hits highest level
California water officials on Friday recorded the biggest accumulation of statewide snow this century for the start of March, a bounty that is likely to grow with coming storms – and further ease the state's drought-time water shortages.
The official March snow survey, which is normally conducted on the first of the month but was postponed two days because of all the snow on the roads, tallied the snowpack in the Sierra Nevada and southern Cascades at 190 percent of average.
At the landmark Phillips Station south of Lake Tahoe, one of the oldest and most central measuring sites where on Friday morning state officials convened for the press, the snowpack was 177 percent average.
“This last week brought a significant amount of snow statewide,” said Sean de Guzman, chief of the snow surveys and water supply forecasting for the California Department of Water Resources.
A spate of cold storms dumped sometimes record snow in late February across parts of California. Travel has become problematic in the mountains. Parks such as Yosemite have closed. Many rural residents have been marooned.
The wet weather, though, will go a long way for drought relief. Nearly a third of the state's water comes from snow, and the melt-off, which typically begins in April and runs into summer, provides a critical boost to reservoirs after the rainy season.
The March survey results top the big snow year in 2017, when statewide total snowpack was 184 percent of average at the start of the month. The numbers fall short, however, of the record snow year in 1983, according to state officials. Guzman said it's possible that 2023 will overtake the high mark set 40 years ago.
“With the next few storms, over the next month, we could actually surpass that,” he said.
Next month's April snow survey remains the most important because it measures the snow at its historical peak, offering a more definitive projection of water supplies for the year. The March snowpack is already measuring 71% higher than the April 1 average.
After the April tally, water agencies across the state as well as the big state and federal water projects generally assess their reserves and determine whether they'll need to restrict water deliveries going forward. Since 2021, many water providers have been asking for, and even mandating, reductions because of the drought.
According to the March measurements, snowpack was greatest in the southern and central Sierra, at 231 percent of average and 196 percent of average. California's far north has received a bit less precipitation, with snowpack measuring 151% of average.
The state snow measurements focus on the amount of water in the snow, not other qualities like depth, because this metric helps gauge future water supplies. The readings are based on a combination of electronic sensors and manual surveys across the state.