A powerful atmospheric river was sweeping across Northern California on Thursday, bringing widespread rain, gusty winds, and high-elevation snow to the Sacramento region, forecasters said.

Rain drops fell into puddles Thursday, sending smalls bits of splashes everywhere. Cars dripped as if slammed by a carwash. And that was in the East Bay, the area where an anticipated atmospheric river storm showed the lesser version of its force as it hit the region.

The storm could trigger dangerous flash floods and mudslides, but it may also extinguish California’s wildfire season.

As a storm moves through Northern California, the real work is just beginning for atmospheric river researchers.

That so-called “rain shadow” often occurs in atmospheric rivers, according to the weather service. The phenomenon causes the lifting of the system as it moves over mountains and hills and leaves less precipitation for areas that surround it.

Evacuation warnings were issued across L.A. County as a storm approached Southern California, bringing the potential for an early end to the fire season as well as risks of flooding and mudslides.

The Bay Area and Monterey Bay was being pounded by heavy rain and strong winds as an atmospheric river storm passed through the region Thursday.

The National Weather Service has issued a flood advisory for much of the Bay Area, including San Francisco, due to an atmospheric river bringing heavy rain to the region Thursday morning.