Tropical storms with such destruction usually sweep over the Atlantic Coast this time of year, but a confluence of unusual weather conditions has put this storm in the Pacific, stretching it into Nevada, parts of Utah, and as far north as Idaho.

Hilary went from a hurricane to a tropical storm by the time it made landfall on Sunday over the northern Baja California peninsula of Mexico with winds of 65 mph. The storm killed a man on Sunday in Mexico’s Baja California Sur, authorities said, after water swept away his car.

The storm forced Death Valley National Park to close and sandbag distributions to take place well inland.

Also on Sunday, Californians felt a much more common natural disaster: a 5.1-magnitude earthquake centered near Ojai, about 80 miles northwest of Los Angeles.

California Gov. Gavin Newsom (D) had declared a state of emergency on Saturday, and Nevada Gov. Joe Lombardo (R) did the same on Sunday.

Newsom said he had witnessed three accidents on the freeway while traveling from San Bernardino County to Los Angeles, illustrating the danger of flooded roads.

“Do your best; be safe. If you don’t have an essential reason to be out there — don’t,” Newsom said late Sunday afternoon.

Standing alongside Newsom during a briefing, Los Angeles Mayor Karen Bass (D) warned that “the worst of the rains is potentially left to come.”

“Right now again, it is critical that Angelenos stay safe and stay home unless directed otherwise by safety officials,” she said. “Avoid unnecessary travel.”

Hilary moved fast toward the interior southwestern United States during the day and into Sunday night.

The city of Henderson, Nev. — home to about 330,000 people in the metro Las Vegas area — planned to hand out sandbags in anticipation of flooding.

“Damaging winds will blow down trees and power lines. Widespread power outages are possible,” the National Weather Service office in Las Vegas warned. “Travel will be difficult, especially for high profile vehicles.”

Hilary, which at one point was a category 4 hurricane off the coast of Mexico, weakened on Sunday but it is expected to merge with another storm system off the West Coast and interact with a massive high-pressure area, keeping the winds going well north of landfall.

Forecasters predicted that rainfall of up to 10 inches in some places will lead to impassable roads, mudslides and other hazards as the storm makes its way inland. The NWS also cautioned residents to be wary of burn scars — areas cleared of trees and other structures by recent wildfires. Those conditions can turn the ground into conduits for rushing water that carries debris such as rocks and trees, as well as vehicles and buildings.

“A good rule of thumb is: If you can look uphill from where you are and see a burnt-out area, you are at risk,” the Weather Service warned.

Conditions deteriorated quickly over Southern California by midday Pacific time Sunday. The Weather Service issued a flash flood warning for areas just to the north of Los Angeles, including Antelope Valley, the Los Angeles County’s mountains and Santa Clarita Valley. Those areas were also hit with wildfires recently as temperatures rose into the triple digits this summer.

California State University at Los Angeles and UCLA canceled classes for Monday, and schools were ordered closed in the Bear Valley Unified School District in San Bernardino County as a precaution. Some businesses, including the Disneyland Resort, closed early on Sunday because of the threat from Hilary.

Los Angeles Unified School District, a district that serves 429,000 students and covers 700 square miles, announced it would be closed on Monday because of the storm.

“Every Los Angeles Unified school has emergency water, food, first aid supplies and search and rescue equipment,” it said on its website.

Municipal public health officials advised people to stay off all Los Angeles County beaches until at least 9 a.m. Thursday because of the possibility of increased bacteria after significant rainfall.

Officials in San Diego and Los Angeles hurriedly opened shelters and warned the thousands of people who are homeless in those cities to seek safety indoors and away from riverbeds ahead of the storm.

As of early afternoon local time, two dozen flood and flash-flood warnings had been issued for Southern California from the border with Mexico to the southern Sierra Nevada and Death Valley. Several severe thunderstorm warnings were issued for an area east of San Diego to near Palm Springs as an intense tropical rain band moved through.

A bulletin from the National Weather Service on Sunday warned that heavy rainfall combined with high winds could lead to potentially catastrophic mudslides, landslides and rock slides in Southern California and into Nevada.

Bass said outreach workers in Los Angeles in helicopters and on the ground were urging ten of thousands of unhoused people to seek shelter.

“We have hundreds of people on our riverbeds. And every time we have a rain event, helicopters drive by as well as hundreds of outreach workers go by in advance to tell them to seek shelter,” Bass said on CBS’s “Face the Nation.”

“If you add in the county, you are talking about more than 70,000 people who are unhoused and the vast majority of them are living outside in tents,” Bass added.

Palm Springs Mayor Grace Garner warned residents to stay inside and prepare for flooding and power outages. More than 60,000 sandbags had been delivered to the residents of Palm Springs, the city posted to Facebook on Sunday afternoon. Less than an hour later, the city posted that it had begun to rain harder and included a photo of standing water at one intersection.

Garner told CBS News’s “Face the Nation” on Sunday morning that the city preemptively closed down the three main roads that are flood-prone.

“We do know that there’s going to be flooding, because like I said, even an inch or two of rain in the desert can cause damage,” Garner said.

Along with flood warnings, Garner said high winds were likely to cause power outages. She encouraged residents to report downed lines to utility giant Southern California Edison as quickly as possible.

In Yuma, Ariz., storm winds downed power lines and trees and took out electricity to thousands of residents, Yuma County Supervisor Jonathan Lines (R), said Sunday. Arizona Public Service reported power outages in the region that, around 5:30 p.m. local time, affected several thousand customers, according to the company’s website.

In Mexico, federal and state officials in both Baja California and Baja California Sur had urged residents on Saturday to brace for possible life-threatening rains and floods and to follow safety precautions. More than 6,500 soldiers were deployed in the days leading up to landfall to set up shelters, organize food banks and prepare for possible emergency rescues. Thousands of other soldiers were deployed to at least four other states.

The Mexican military on Sunday said it had evacuated more than 2,500 people in Baja California who were in areas vulnerable to storm damage or who could no longer stay in their homes.

In the United States, FEMA Administrator Deanne Criswell said that people need to take Hilary seriously, adding that “a more active Pacific season” had been expected with the presence of El Niño.

“We are seeing this increase in the number of severe weather events, but not just an increase in the number. It’s the severity of these events,” Criswell said on CNN’s “State of the Union.” “We have to also look at what is the change in the climate doing to these severe weather events. What is the risk going to look like into the future?”

The National Hurricane Center is already busy with active tropical conditions in the Atlantic. On Sunday, it posted information on newly formed Tropical Storm Emily in the Central Atlantic Ocean and Tropical Storm Franklin in the Caribbean. It was also following a tropical depression and two other tropical disturbances in the Atlantic and the Gulf of Mexico that had chances of developing into cyclones.

A researcher at University of California at Irvine said that Southern California’s infrastructure may not be able to handle the expected rainfall from Tropical Storm Hilary.

“I am personally worried about the combination of infrastructure that’s undersized to contain an event of this magnitude and an area that has experienced a number of wildfires,” said Brett Sanders, a professor of civil and environmental engineering.

Rozsa reported from West Palm Beach, Fla., and Livingston, Javaid and Villegas reported from Washington. Mary Beth Sheridan in Mexico City; Dan Michalski in Las Vegas; Diana Leonard in San Diego; Yvonne Wingett Sanchez in Phoenix; Scott Wilson in Santa Barbara; Ben Brasch in Atlanta; and Kyle Rempfer, Taylor Telford, Jason Samenow and Dan Stillman in Washington contributed to this report.