According to several historical and meteorological sources, the only tropical storm documented to make landfall in Southern California in the 20th century rolled into Long Beach on Sept. 25, 1939. The former hurricane didn't have a name at the time and came as a surprise to the locals. The National Weather Service office in Oxnard revisited the event in a Facebook post today and included the graphic here showing the storm track.
Could a hurricane reach southern California? On Sept. 25, 1939, an unnamed tropical storm hit Long Beach, the only documented tropical system to make landfall in SoCal. The storm resulted in widespread flooding, large waves, and many fatalities. Downtown Los Angeles received 5.24 inches of rain in 24-hours which still stands today as the daily record.
The weather was warm prior to the arrival of the tropical storm due to offshore Santa Ana-like winds. Many people were caught off-guard on boats trying to return from the Channel Islands. Up to 45 people were killed in boat-related accidents, and possibly 45-50 more died in flooding related to the storm.
There was no government weather forecast office in Los Angeles at the time of the tropical storm. That changed by February 1940, when the Weather Bureau established a forecast office for all of southern California.
Today the Los Angeles National Weather Service Forecast Office is located in Oxnard, CA, and we still prepare and train our staff on the possibility of a tropical storm or hurricane reaching the Los Angeles area. Rare events like this can be the most devastating, much like big earthquakes or extreme El Nino winters.
Are you prepared?
There is some video online of that day. That was just over a year after the March, 1938 rain cycle that inundated big swaths of Los Angeles, forced the postponement of the Oscars and provided the final political push to channelize the Los Angeles River in concrete and to prevent future flooding.