California's Tropical Storm And Hurricane History

C​alifornia is rarely hit by tropical storms, but remnants of former tropical storms and hurricanes have often wrung out flooding rain in parts of the Golden State.

T​his comes to light because Hurricane Hilary is expected to track near Mexico's Baja California and will likely have some impacts on California and other parts of the West in the coming days.

T​o be clear, Hilary's center will steadily weaken and not directly move into Southern California as a hurricane. But impacts including locally heavy rain, some strong wind gusts and high surf will affect much of the Southland, regardless.

(​MORE: Hurricane Hillary's Forecast)

S​o let's shed some light on California's brushes with tropical systems in the past and explain why they're usually, but not always protected.

Where Do Most Eastern Pacific Storms Track?

T​he majority of Eastern Pacific tropical storms and hurricanes are steered toward the west-northwest by high pressure into open water south of Baja California's southern tip.

However, i​f high pressure to their north isn't strong enough, they can occasionally curl north, then northeast into mainland Mexico or the Baja Peninsula.

A​nd in the case of Hilary, if the high pressure is too strong, storms can rarely accelerate in a much weakened form northward or clockwise across the West mostly as a batch of moisture.

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W​hy Do So Few Make It To California?

As you noticed in the map above, there are very few tracks that made it as far north as California.

Nora in 1997 is the only storm s​ince the middle of the 20th century to maintain tropical storm intensity while its center was over California.

T​he rest of those were either tropical depressions or remnants of former storms.

California is usually protected from direct hits by hurricanes and tropical storms because the warm ocean water that these storms feed off of drops off dramatically north of the southern tip of Baja California. This cooler water is supplied by the southward-moving ocean current known as the California Current.

Another reason is subtropical high pressure usually provides dry, sinking, stable air near the West Coast in summer that suppresses thunderstorms needed to maintain tropical storms and hurricanes.

Hurricane or tropical storms that attempt to move north into that hostile environment tend to weaken quickly.

W​hat Are Some Recent Examples?

T​here are quite a number of cases in which remnants of former tropical storms and hurricanes have impacted parts of the Golden State, as the National Weather Service office in San Diego documented.

In August 2020, moisture from short-lived Tropical Storm Fausto played a role in a rare flareup of lightning in Northern California, including around the Bay Area. The lightning started several devastating wildfires in the region since the storms had little rainfall.

I​n Sept. 1997, the former Hurricane Nora dumped up to 5.5 inches of rain in Southern California, triggering street flooding in San Diego and Palm Springs. Winds knocked out power to 125,000 customers and up to 20-foot waves produced tidal flooding at Seal Beach.

Southern California's most destructive flooding from a recent former tropical storm or hurricane was in 1976. The remnant of the former Hurricane Kathleen surged north through the Mojave Desert and dumped up to 14.76 inches of rain, a state record for any tropical cyclone or remnant.

Record flooding overwhelmed streams above the Coachella Valley and much of the Imperial Valley was flooded. More than 70% of the town of Ocotillo 65 miles east of San Diego was buried in sand and mud up to 10 feet deep. Six people died. Sections of Interstate 8 and other roads were washed away.

T​otal damage from the flooding was estimated at $160 million, according to the NWS.

Have There Been Any Direct Hits?

T​he Los Angeles and San Diego metro areas have only been directly hit by two systems of at least tropical storm strength in their recorded history.

It's been a long time since that happened.

In September 1939, a tropical storm with winds of 50 mph made landfall near Long Beach. Downtown LA picked up 5.62 inches of rain from the storm, including 3.96 inches on Sept. 25.

Flooding caused $2 million of property damage. High winds surprised the shipping industry in the area and killed 45 people. Since this "Long Beach Storm" took the Weather Bureau's San Francisco office by surprise, a new office was opened in Southern California the following February.

A 2004 study uncovered the only known hurricane to hit Southern California that tracked up the coast from San Diego to Long Beach on Oct. 2, 1858. While San Diego was only a settlement of about 4,000 residents at the time, wind damage was widespread near the coast and some flooding also occurred inland.

So, while extremely rare, it is possible for a hurricane or tropical storm to make it into Southern California in the future.

This could occur again if the ocean off the California coast warms just enough, and a hurricane or tropical storm moves fast enough to avoid too much weakening.

Hurricane Linda in 1997 is a recent cautionary tale.

I​n a hurricane season with ocean water warmed by a strong El Niño, Linda was forecast by some computer models, and for a brief time by the National Hurricane Center, to approach San Diego as a tropical storm or Category 1 hurricane.

F​ortunately, Linda took a more typical west-northwest path out to sea well south of both the Baja Peninsula and Southern California.

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