Hurricane Hilary is expected to weaken to a tropical storm as it enters colder water off the Southern California coast, bringing rare August rainfall to Los Angeles during the region's driest month of the year.
No tropical storm has made landfall in Southern California since Sept. 25, 1939, when a system lost its hurricane status just before moving onshore in Long Beach.
The impact was devastating.
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The system formed Sept. 15 as a tropical depression off the south coast of Central America before intensifying to a hurricane. After losing hurricane strength, the tropical storm made landfall in the San Pedro-Long Beach area early Sept. 25 with winds at gale strength.
The storm packed enough power to cause death and significant destruction, bringing sustained wind gusts of 50 mph and more than 5.6 inches of rain to Los Angeles in a 24-hour period. More than 11 inches of rain were reported on Mt. Wilson.
Forty-five deaths were reported. Property losses were estimated at $2 million.
A recorded storm has never moved into California as a hurricane. Some have come close, including Norman in 1978, Doreen in 1977, Hyacinth in 1972 and Jen-Kaht in 1963. That's due to cooler ocean water and a regional high-pressure system that weakens storms as they get closer to the coastline. Tropical storms and hurricanes feed off warmer ocean water, which drops off north of Baja California's southern tip.
"Our weather is such that the systems break apart before they arrive here," said NBC4 forecaster Belen De Leon.
Strong high pressure pushes hurricanes toward the west-northwest and into open water. If high pressure to the north isn't strong enough, hurricanes may track north and northeast into Mexico or the Baja California Peninsula.
Although no tropical storm has made landfall in SoCal this century, that doesn't mean the region hasn't felt the impacts. Most recently, Hurricane Kay in 2022, during which a person was killed when a house was caught in a debris flow in San Bernardino County.
Hilary is expected to lose its hurricane status as it closes in on the U.S.-Mexico border. Its remnants will deliver widespread rain in Southern California with the heaviest rain arriving late Sunday and into Monday.