California snowpack rises after warm storm

Rain soaked into the Sierra Nevada snowpack and refroze, raising California’s median snow water equivalent from 70% to 75% between Monday and Wednesday, according to UC Berkeley monitoring reported by SFGATE. Statewide snowpack remains at about 61% of average peak, with regional differences reported.

A warm storm moved through the Sierra Nevada this week, with rain seeping into existing snow and refreezing. That process increased the statewide median snow water equivalent (SWE) by five percentage points from Monday to Wednesday, according to University of California Berkeley monitoring reported by SFGATE. SWE measures how much water is stored in the snowpack to feed rivers and reservoirs as temperatures rise. Officials and researchers noted the recent storms have helped rebuild parts of the snowpack and raised some reservoir levels. Key details: - University of California Berkeley monitoring, as reported by SFGATE, shows median SWE rose from 70% on Monday to 75% by Wednesday. - Official figures place California’s overall snowpack at about 61% of the average peak. - Regional figures reported by SFGATE list the Southern Sierra at 95% of normal, the Central Sierra at 74%, and the Northern Sierra at 54%. - Recent back-to-back winter storms and midwinter rain helped raise some reservoir levels and contributed to the SWE increase. - Statewide precipitation since October has averaged roughly 18 inches, about 116% of normal, according to SFGATE. - The California Department of Water Resources said the system delivered rain and Sierra snowfall that will help rebuild snowpack, and UC Berkeley’s Central Sierra Snow Laboratory director noted SWE is the key metric for water resources and that an increase means more water stored in the snowpack. Summary: The recent warm storm produced rain that refroze in the Sierra snowpack and raised median SWE by five percentage points, modestly increasing stored water for rivers and reservoirs. Despite this improvement and wetter-than-normal precipitation since October, statewide snowpack remains below the average peak. Undetermined at this time.