Southern California’s Brief yet Deadly Tropical Storm History

Hurricane Hilary, currently barreling towards Southern California, is anticipated to weaken as it encounters colder waters off the coast. This rare occurrence is likely to bring much-needed rainfall to the region during the typically dry month of August.

Southern California has not seen a tropical storm make landfall since September 25, 1939, when a system lost its hurricane status just moments before reaching Long Beach. The impact of this historical event was nothing short of devastating.

The system initially formed on September 15 as a tropical depression off the coast of Central America before intensifying into a hurricane. Though it eventually lost its hurricane strength, the tropical storm landed in the San Pedro-Long Beach area on the early morning of September 25, accompanied by powerful gale-force winds.

The intensity of the storm was staggering, resulting in numerous deaths and significant destruction in its wake. The region experienced sustained wind gusts of 50 mph and received more than 5.6 inches of rainfall within a 24-hour period. The toll was even greater on Mt. Wilson, where rainfall reached an astonishing 11 inches.

Tragically, the storm claimed the lives of 45 individuals and resulted in an estimated $2 million in property losses. This catastrophic event would mark the first and only time a storm of this magnitude made landfall in California as a hurricane.

This unique phenomenon can be attributed to the cooler ocean waters near the Californian coastline and the presence of a regional high-pressure system that weakens approaching storms. Tropical storms and hurricanes derive their strength from warm ocean waters, which are absent north of Baja California’s southern tip.

Belen De Leon, a forecaster from NBC4, explained, “Our weather patterns are such that the systems disintegrate before reaching our area.” Strong high-pressure systems in the region divert hurricanes towards the west-northwest and into open waters. In cases where the northern high-pressure system isn’t robust enough, hurricanes may veer north or northeast towards Mexico or the Baja California Peninsula.

However, while no tropical storm has made landfall in Southern California since the start of the 21st century, the region has not escaped the impacts entirely. In 2022, Hurricane Kay resulted in a tragic fatality when a house was swept away in a debris flow in San Bernardino County.

As Hurricane Hilary approaches the U.S.-Mexico border, it is anticipated to lose its hurricane designation. Nonetheless, its remnants are projected to bring widespread rainfall to Southern California, with the most substantial precipitation anticipated late on Sunday and into Monday. This development offers a glimmer of hope for the parched region, even as it braves the potential challenges associated with tropical weather systems.