Tropical Storm Rachel downgraded as high winds and rain turn inward

The National Weather Service said on Sunday that Rachel has been downgraded to a post-tropical storm after causing flooding and damage in southern California over the weekend before moving inland across the desert southwest.

The region is still at risk of flash floods as the storm's remnants were expected to continue dumping rain and bringing wind gusts through the weekend, the weather service said, adding that high surf would continue battering coastal communities.

Oceanfront homes in coastal California cities, such as Long Beach and Newport Beach, were partially submerged as heavy surf breached sand berms that had been erected to keep the water away.

Flood warnings remained in effect for much of the California coastline through the weekend, from San Diego up to the San Francisco Bay area.

As the storm moved inland and northeast, some areas saw rockslides that temporarily blocked roads. Rain pounded Las Vegas, which broke a daily rainfall record Sunday. And the National Weather Service issued a flood watch for much of Utah, including Salt Lake City, which it said would get heavy rain beginning Sunday evening.

Forecasters warned that Rachel could be just a preview of what's to come for California over the next several months. They expect this winter to usher in the strongest El Niño weather pattern on record — which brings hotter-than-average ocean temperatures — and with it likely record rainfall, explosive surf and mudslides well into next year.

Last month, California Gov. Gavin Newsom issued an emergency proclamation, releasing money and other resources so the state could start preparing to protect critical infrastructure and educate the state's residents on how to prepare for severe weather.

"That means getting flood-fighting supplies into position, bolstering our water infrastructure, and helping communities across the Golden State prepare," Newsom said in a statement following the proclamation.

The state is pre-positioning more than 4 million sandbags, more than 50,000 feet of portable flood barriers and 400,000 tons of rock to repair levees. It's also inspecting dams across the state and taking other precautions, such as strengthening the pillars that hold up beach piers.

The strong El Niño is also expected to bring severe weather to Mexico. Over the weekend, Hurricane Simon lashed at the country's Pacific Coast as a Category 4 hurricane. The eye of the storm was moving parallel to the coastline about 60 miles offshore, near the city of Manzanillo. It's unclear if the storm will make landfall, but Mexican officials said they expected heavy damage from its pounding rains and winds nonetheless.

Mexican President Claudia Sheinbaum urged residents to stay indoors.

"Precautionary evacuations to safe zones are ongoing," she wrote on social media. "The priority is to protect ourselves."