
An atmospheric river will bring heavy rainfall to lower elevations of California this week, and heavy snow to the Sierra Nevada mountains. Flash flooding, some of which may be locally considerable, will be a concern on the western foothills of the Sierra Nevada mountains through Tuesday. Landslides, rockfalls and mudslides are possible in the Southern California mountains. Read More >
Coverage is affected by many factors.
Read the Coverage Map Notes below to understand these factors on the state and individual maps.
The coverage statistics and maps are calculated using a computer model and station data, assuming ideal conditions. Actual coverage may be 5 to 10 percent below the computer-predicted coverage due to the following factors: