SAN FRANCISCO (AP) — The first in a week of storms brought gusty winds, rain and snow to California on Tuesday, starting in the north and spreading southward.

There were numerous reports of roadway flooding and downed trees and branches, the National Weather Service said.

Winter storm warnings were issued for the Sierra Nevada, where motorists were advised that the combination of winds and snow could make travel hazardous.

The greater Lake Tahoe area and Mono County were warned to expect heavy snow with wind gusts around 50 mph (80 kph), and up to 100 mph (161 kph) along Sierra ridgetops. Lake Tahoe was expected to have waves that could capsize small vessels.

Downtown San Francisco had received more than an inch (2.5 centimeters) of rain and Mount Tamalpais had more than 4 inches (10 cm) before dawn.

The weather system, an atmospheric river spawned by a low pressure off the Pacific Northwest, was spreading slowly down the coast and was expected to reach Los Angeles by evening.

Forecasters said California will experience unsettled weather through the week.