This time of year in California the weather can switch from spring-like temperatures in the high 70s to a winter-sized storm in a span of 24 hours. Northern California is bracing for that exact scenario on Friday, when a drastic turn in the weather is expected to switch from sunshine to moderate rain and heavy snowfall.
The heaviest precipitation will occur Friday and continue into Saturday, with snow levels in the sierras initially around 6,000 feet before dropping to between 2,500-3,000 by Sunday, according to the National Weather Service (NWS). Thunderstorms in the valley are possible for Friday and Saturday.
The combination of a wet winter and eventual sustained warm weather elevates the possibility of spring snowmelt flooding in various areas throughout Northern California. The Hydrologic Outlook, as provided by NWS and the California Nevada River Forecast Center (CNRFC), presents a considerable risk for spring flood potential due to above average snowpack in the sierras.
Among the areas of concern include mountainous parts of the Cascades and the Sierra Nevada as well as lower elevation systems such as the San Joaquin River and Tulare Basin. Snowmelt volume could force higher than normal releases from large reservoirs, adding additional stress and impacting lower-elevated areas throughout the spring and into early summer.
Remember, heavy rainfall alone is capable of causing extensive flooding, as well as spring snowmelt. With a deep snowpack this year, the potential of an extended snowmelt season could stretch to mid-summer.
California is still recovering from a devastating winter. Four separate Major Disaster Declarations were approved by President Donald J. Trump, including the most recent on April 2.
Click here to learn more about the disaster declarations as well as statewide storm recovery resources.