California has received less than 50 percent of its average rainfall so far this year, and its snowpack is at about 59 percent of its average for April 1. The conditions have resulted in water year 2020/21 being tied for the third driest year on record.
The Department of Water Resources conducted its fourth manual snow survey of the year at Phillips Station in the Sierra Nevada Mountains on Thursday. The snowpack was 83 percent of its average for the location. Members of DWR’s snow survey and water supply forecast section recorded a snow depth of 49.5 inches and a snow water content of 21 inches — a measurement of how much liquid water is contained within the snowpack.
“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 Sean de Guzman, chief of DWR’s snow surveys and water supply forecasting section. “…The few storms that have impacted California have actually been colder storms, which have brought a lot more snow than rain compared to a typical year.”
April 1 is typically when California’s snowpack is the deepest and has the highest snow water content. DWR utilizes the data collected from its snow surveys to better forecast the amount of water that will eventually runoff into the state’s reservoirs when the snowpack melts — the Sierra snowpack accounts for 30 percent of the state’s fresh water supply in an average year.
The amount of water expected to enter California’s reservoirs when the snowpack melts is currently projected to be just 58 percent of average.
“State agencies, water suppliers and Californians are more prepared than ever to adapt to dry conditions and meet the challenges that may be ahead,” said DWR Director Karla Nemeth in a press release. “With climate change impacting how precipitation falls in California, ongoing water efficiency and long-term efforts like recycling water, capturing stormwater, and planting water-friendly landscapes are essential to securing California’s water future.”
De Guzman said the state’s reservoirs continue to show the impacts of the current dry spell. Lake Oroville was at 53 percent of its average as of Thursday, while Lake Shasta was at 65 percent of its average. Statewide, de Guzman said, California’s largest reservoirs were only storing about half of their total capacity.
As the snowpack starts to melt in the coming weeks and months, the big unknowns are how dry the soils are beneath the snowpack and how much water they will absorb before runoff occurs. De Guzman said the next few weeks will be critical in terms of watching to see how much of the snowpack enters the state’s reservoirs.
“Even though we have drought-like conditions, Californians as a whole have actually been conserving a lot more water than compared to where we were before 2012 when the previous drought started,” de Guzman said. “So, a lot of the public has continued their efforts, which is a great sign, and we need to continue to do that.”
DWR’s next manual snow survey at Phillips Station is tentatively scheduled for April 29.