Snowpack about 90 miles north of Sonora showed 43.5 inches of snow depth Wednesday and snow water equivalent of 16.5 inches, which is 66 percent of average for the date and location.
The manual snow survey results from Phillips Station off Highway 50 confirmed the 2019-2020 wet season has been a below average to dry year so far, state Department of Water Resources staff said Wednesday.
March storms that brought 5 inches of precipitation to Mother Lode watersheds and other parts of the Sierra Nevada were not enough to offset what was already a dry winter season, which included the driest February on record.
Due to the ongoing COVID-19 pandemic, Department of Water Resources staff did their fourth snow survey of 2020 on Wednesday with limited staff and without news media.
Measurements from electronic snow sensors in the Sierra Nevada and elsewhere in California showed the statewide snowpack’s water equivalent is 15.2 inches, or 53 percent of the April average. Snowpack was at 56 percent of average for April 1 in the Central Sierra.
“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,” Karlan Nemeth, the state DWR director, said Wednesday. “California’s climate continues to show extreme unpredictability, and February’s record dryness is a clear example of the extremes associated with climate change.”
California watersheds are being subjected to increased extremes and variability due to climate change, state water resources staff said. In one year, California has gone from having the fifth-best recorded snowpack to one of the 10 worst.
“Over the last decade, California’s snowpack has been alternating between extremely wet and extremely dry,” Sean de Guzman, chief of the state DWR snow survey and water supply forecast section. “In the past 10 years, we’ve seen three of our smallest snowpacks on record, but we’ve also seen three of our largest snowpacks on record.”
As of Wednesday principal watersheds in the Mother Lode, including the Stanislaus and Tuolumne river basins, had received 18 inches of precipitation so far this current water year, which started Oct. 1. That’s 54 percent of average for the date April 1, according to a five station index that includes Calaveras Big Trees and Hetch Hetchy.
Major reservoirs in the Mother Lode were 60 percent to 90 percent full. On the Mokelumne River, Pardee was 92 percent full and Camanche was 66 percent full. New Melones on the Stanislaus River, the state’s fourth-largest capacity reservoir, was 79 percent full. Hetch Hetchy on the Tuolumne River in Yosemite National Park was 64 percent full, Cherry was 82 percent full, and Don Pedro, the state’s sixth-largest capacity reservoir, was 81 percent full. McClure on the Merced River was 62 percent full.
This winter and spring so far can be remembered for December storms that provided a decent start for snowpack in the Central Sierra, a mostly dry start to 2020 with late January storms that brought needed precipitation while snowpack remained below average, and the driest February on record in the Golden State. March brought about 5 inches of precipitation to Mother Lode watersheds.
Whether surveyors do a fifth snow survey in May will depend on conditions at the time, Chris Orrock with the California Department of Water Resources said Tuesday, estimating chances of a May survey at 50/50.
The most recent manual survey at Phillips Station was Feb. 27, where state water staff recorded 29 inches of snow depth, and snow water equivalent of 11.5 inches, which was 47 percent of average for the location. Snow water equivalent is the amount of water contained in snowpack, and it can help water managers downstream forecast spring runoff.
Snowpack surveys are critical for all water managers in California, including dam operators, farmers, contractors and providers like Tuolumne Utilities District. Data from snow surveys is factored into determining how much water will be allocated at various points downstream from the crest of the Central Sierra, including the State Water Project, which brings water to more than 27 million Californians and 750,000 acres devoted to agriculture.
Contact Guy McCarthy at email@example.com or 588-4585. Follow him on Twitter at @GuyMcCarthy.