Hurricane Hilary becomes a Category 4 Storm as it Nears Mexico and California

Hurricane Hilary was charging through the Pacific Ocean on Saturday heading toward Mexico and the United States, where it could cause heavy rain and dangerous flooding even after weakening.

The storm, which weakened Saturday night to a Category 4 hurricane, was about 285 miles south-southeast of Punta Eugenia, Mexico, and about 640 miles south-southeast of San Diego as of 2 p.m. Saturday in Los Angeles, the National Weather Service’s National Hurricane Center said in an advisory. Meteorologists have said that the storm may cause “life-threatening” and potentially “catastrophic” flooding in Baja and the Southwestern United States, starting this weekend.

The tropical storm warning in effect early Saturday indicated that tropical storm conditions were possible within the coverage area over the next 36 hours. The area stretched from the California-Mexico border to Point Mugu, around 40 miles west of Santa Monica by road, and includes Catalina Island. The warning was the first ever issued for Southern California, according to the hurricane center.

Hilary had sustained winds near 130 mph, the Hurricane Center said. Tropical cyclones that have sustained winds of 39 mph earn a name. Once winds reach 74 mph, a storm becomes a hurricane, and, at 130 mph, it becomes a major hurricane.

A number of events in the Los Angeles area this weekend, including a Major League Soccer match and several Major League Baseball games, have been rescheduled because of the approaching storm.

Hilary formed as a tropical storm off the coast of Manzanillo, Mexico, on Wednesday and began moving west-northwest toward Baja California as it strengthened.

The hurricane is expected to continue to weaken but to remain a hurricane as it approaches the west coast of the Baja California Peninsula on Saturday. It will then most likely become a tropical storm before reaching Southern California by Sunday.

Hilary’s exact landfall likely will not make much of a difference when it comes to the expected hazards in the region, meteorologists said.

The storm will bring up to 6 inches of rain across portions of the Baja California Peninsula through Sunday night, with isolated amounts up to 10 inches and the possibility of flash flooding.

Portions of Southern California and Southern Nevada will record similar rainfall totals through Tuesday morning, which could lead to “dangerous and locally catastrophic flooding,” forecasters said. Some arid regions of Nevada could record one to two years’ worth of rain in a single day, the Weather Prediction Center said.

A flood watch was issued for much of Southern California, including Los Angeles, Riverside, Orange, San Bernardino, San Diego and Ventura counties. Other areas across the West can expect a few inches of rain.

Residents in Southern California raced to prepare sandbags and fill generators before Hilary’s arrival as emergency officials prepared evacuation centers. Some expressed particular concern about the impact on mountain and desert regions.

Forecasters said strong winds could occur before the storm’s center. Those winds, combined with heavy rain, could lead to mudslides and landslides that could block roadways, the Weather Prediction Center said in an update Saturday.

“Towns could get cut off,” the center said.

Mexico’s government issued a hurricane warning for the Baja California peninsula from Punta Abreojos to Cabo San Quintin. A hurricane watch is also in effect for the Baja California Peninsula’s west coast north of Cabo San Quintin to Ensenada.

A tropical storm warning and watch were also issued for multiple regions of the peninsula and mainland Mexico.

The Mexican army mobilized troops in anticipation of severe damage to infrastructure.

Areas of heavy rain were covering portions of the Baja California Peninsula and the Southwest on Saturday, the Hurricane Center said.

Hilary also produced high seas, with waves reaching heights over 40 feet off the coast of Baja California and in the Gulf of California, according to the center.

The Eastern Pacific hurricane season has been active this summer, but most storms have tracked west toward Hawaii, including Hurricane Dora, which helped enhance extreme winds that led to the devastating wildfires on Maui.

It is “exceedingly rare” for a tropical storm to come off the ocean and make landfall in California, said Stefanie Sullivan, a forecaster with the National Weather Service in San Diego. The only tropical cyclone to truly make landfall in Southern California was an unnamed storm in 1939 that reached Long Beach, she said.

However, storms have come close or weakened before coming ashore, still causing flooding and dangerous winds, such as Kay, a post-tropical cyclone, last year. Sometimes storms even move across the state from Mexico; in 1997, Hurricane Nora made landfall in Baja California before moving inland and reaching Arizona as a tropical storm.

Complicating things in the Pacific this year is the development of El Nino, the intermittent, large-scale weather pattern that can have wide-ranging effects on weather worldwide.

There is a consensus among scientists that hurricanes are becoming more powerful because of climate change. Although there might not be more named storms overall, the likelihood of major hurricanes is increasing.

Climate change is also affecting the amount of rain that storms can produce. In a warming world, the air can hold more moisture, which means a named storm can hold and produce more rainfall, as Hurricane Harvey did in Texas in 2017, when some areas received more than 40 inches of rain in less than 48 hours.

Researchers have also found that storms have slowed down over the past few decades.

When a storm slows down over water, it increases the amount of moisture it can absorb. When the storm slows over land, it increases the amount of rain that falls over a single location, as with Hurricane Dorian in 2019, which slowed to a crawl over the northwestern Bahamas, resulting in 22.84 inches of rain at Hope Town over the storm’s duration.

Research shows climate change might have other effects as well, including storm surge, rapid intensification and a broader reach of tropical systems.

This article originally appeared in The New York Times.