A storm is dropping rounds of heavy rain on more than 22 million people across Southern California on Saturday, and the rainfall could spark dangerous flash flooding, mudslides and debris flows.

Here’s the latest:

The first round of heavy rain is slamming the region early Saturday morning, and the second round will hit between 11 a.m. and 4 p.m. local time.

Rainfall rates could top 1 inch per hour and scattered thunderstorms could bring strong winds, lightning and potentially hail.

Flood watches are in effect in Los Angeles, Santa Barbara, Riverside and San Diego through Saturday evening. A level 3 out of 4 risk for excessive rainfall and flash flooding is in place for the LA and Santa Barbara areas.

Wildfire burn scar areas are of serious concern on Saturday because they’re extremely prone to flash flooding, mudslides and debris flows. But flooding and mudslides pose a major threat to Southern California in general, beyond just burn scar areas.

Evacuation warnings are in place for certain areas with burn scars, while some evacuation orders have been issued for select areas that have a heightened risk of mudslides and debris flows.

The mountains of Santa Barbara, Ventura and Los Angeles counties will likely see some of the biggest rain totals, with as much as 4 to 6 inches of rain. On average, LA records 0.8 inches of rain in the entire month of November.

The heavy rain will end Saturday night, but an unsettled weather pattern will stick around into early next week with more wet weather on the way. Flash flooding, debris flows, mudslides and landslides will remain concerns for several days as more rain falls over saturated soils and very sensitive areas.