A winter storm is moving out of the San Diego area Friday but brought much-needed rainfall and gusty winds that led to some flooding and downed trees.

The worst of the rainfall in the first atmospheric river to hit San Diego this year has passed, but the impacts will still be felt for the next few days at the region’s beaches.

As heavy rain from a large storm subsided, officials in Southern California said rock and mudslides remain a threat.

The California Highway Patrol reported 90 crashes on Thursday afternoon compared to about 50 wrecks on an average sunny day. “It’s really not as bad as what we’ve sometimes seen in the past,” CHP ...