Rains slow as Hilary moves north and leaves Southern California underwater

For the latest updates on this story, follow our digital live coverage.

Tropical Storm Hilary poured rain across Southern California throughout Sunday night, leaving millions of people at flood risk, thousands of homes without power and the country's second-largest school district closed.

The first tropical storm to hit the region in nine decades dropped as much as 7 inches of rainwater in some mountain regions and up to 4 inches in lower lying areas.

Early Monday, officials reclassified the storm as a post-tropical cyclone. The center of the storm is expected to travel north through Nevada today. Officials in Las Vegas warned of wind gusts of up to 75 miles per hour. Flash flood warnings will remain in effect there until 6:30 a.m. PDT.

The storm traveled from northern Baja California in Mexico into the United States, drenching California along the coast, in the mountains, and in the Coachella Valley, home to the desert city of Palm Springs.

The National Weather Service cautioned that heavy rain had passed in some areas, such as Ventura County, but lighter rain still posed potentially deadly threats. Just after midnight, it reported that rain was falling at a rate of 0.5 to 1 inch of rain per hour in the San Gabriel Mountains in Los Angeles, and that rock and mudslides were occurring.

"Our message today remains the same. Stay safe. Stay informed. Stay home," said Los Angeles Mayor Karen Bass at a Sunday news conference ahead of the rain's peak. She said she'd spoken with Vice President Kamala Harris, who offered federal support.

The Los Angeles Unified School District canceled all classes and before and after school programs on Monday. "Our school district covers 700 square miles. There will be impact in some areas," said Alberto Carvalho, the district's superintendent. "We cannot inspect those areas, those schools ... so the prudent thing to do to avoid harm ... is to call off schools for [Monday]."

Carvalho said he expects class to resume as normal Tuesday morning.

Flash flood watches in Los Angeles County remained in effect until 3 a.m. Monday PDT. A flash flood warning for parts of San Bernardino and Inyo Counties — east and north of LA — was in effect until 5 a.m.

Southern California Edison, a regional electric provider, reported more than a hundred power outages that left some 20,000 customers without service.

In the Coachella Valley, a desert stretch of inland California unaccustomed to downpours, several cities reported that 911 services were down. One of them, Palm Springs had recorded more than 3 inches of rain Sunday evening.

Part of Interstate 10, which cuts through the valley west of Joshua National Tree National Park, were closed because of flooding and debris, according to the California Department of Transportation.

Copyright 2023 NPR. To see more, visit https://www.npr.org.