DWR is Taking Action as High Temperatures Prompt Early Snow Runoff

Early season heat is rapidly wiping out California’s giant, frozen reservoir – the Sierra Nevada snowpack. Snow is melting fast, even at the highest elevations. In the last 12 days alone, the statewide snowpack has begun melting, on average, 1 percent per day, according to data taken from a network of snow pillows -- sensors that weigh overlying snow to help hydrologists calculate how much water will eventually run off mountain slopes and into rivers and reservoirs.

Mountain snowpack provides as much as a third of the water Californians use.

With high (and perhaps record-breaking) temperatures in the forecast for mid-March, this melt may even accelerate. If this trend continues, California could experience the second-lowest April 1 snowpack in recorded California history. The lowest April 1 snowpack was in 2015, when the statewide snowpack stood at just five percent. April 1 is typically when we see our peak snowpack. This year that peak likely occurred in mid-February. Early season heat is rapidly wiping out California’s giant, frozen reservoir – the Sierra Nevada snowpack. Snow is melting fast, even at the highest elevations. In the last 12 days alone, the statewide snowpack has begun melting, on average, 1 percent per day, according to data taken from a network of snow pillows -- sensors that weigh overlying snow to help hydrologists calculate how much water will eventually run off mountain slopes and into rivers and reservoirs.

To get eyes and measurements in several watersheds to better understand snowmelt conditions to inform runoff forecasts, DWR and several of its partners in the California Cooperative Snow Surveys program will conduct mid-month snow surveys in several watersheds over the next two weeks. Additionally, DWR will utilize Airborne Snow Observatory flights in some watersheds to help assess the snowmelt conditions.

Adjusting operations in real-time helps DWR and water managers across the state better prepare for changing conditions and work to capture and store as much water as possible for use during our dry summer months. This benefits not only communities but our environment.

Learn more about recent improvements to DWR’s snowmelt runoff forecasting here.