An extremely rare and historically significant storm pounded Santa Monica and the greater Los Angeles area on Sunday, as Tropical Storm Hilary brought heavy downpours almost unheard of for the month of August.
Spilling from Sunday into the overnight hours of Monday, Hilary’s 36-hour total rainfall observed at the National Weather Service’s Santa Monica Municipal Airport station was 3.52 inches. Another observational site used by the NWS, provided by the California Irrigation Management Information System (CIMIS) on the 900 block of Franklin Ave., recorded a similar 3.40-inch 36-hour total.
Sunday’s deluge of rain and gusty winds began in the late morning hours, remaining consistent throughout the afternoon and evening. A flash flood warning was put into effect by the NWS just before 12 p.m. Sunday, a warning that was extended throughout the day.
Despite the warning, the Santa Monica Office of Emergency Management noted that the storm had “no significant effect on call volume” and no major safety concerns for local responders, and that call volume was similar to “any other rainy day.”
The 24-hour rainfall total recorded by the Santa Monica Airport station was 2.48 inches, a near record-breaking total in the city for the month of August. Per the Western Regional Climate Center’s historical data section, which goes back to the early 20th century, the only August 24-hour rainfall to top Sunday’s took place on Aug. 17, 1977. On that date, according to an observation station at the Santa Monica Pier, 2.81 inches fell in the city.
Downpours also approached the peak 24-hour rainfall totals in 2023, a year that began with multiple atmospheric rivers striking the area. At the Santa Monica Airport station, the 24-hour peak of 2023 was between the morning of March 14 and the morning of March 15, when 2.69 inches of rain was recorded.
Another impact in the area came in the form of wind gusts, which stayed steady between 20-25 mph from 12 p.m. to 6 p.m. Sunday. A peak wind gust of 29 mph was recorded at 4:51 p.m. Rough surf was reported as well, with waves steadily rising above 3 feet in height throughout Sunday, according to the National Data Buoy Center.
Tropical Storm Hilary was the first of its kind to hit Southern California in 84 years, impacting citizens throughout greater Los Angeles. Long Beach resident Lucy Quevado told the Daily Press that closure of local establishments affected her day, and that she’ll be better prepared for the next storm. “It was a lot of waves and very strong winds, and also it didn’t stop raining all day,” Quevado said.
According to the Associated Press, no deaths or serious injuries have been reported in California due to the storm as of Monday, a much different case than the state’s last tropical storm in September 1939, which killed nearly 100 people on land and at sea.
Along with the threats from rain and wind, a 5.1-magnitude earthquake struck about 4 miles (7 kilometers) southeast of the mountain community of Ojai, about 80 miles (130 kilometers) northwest of downtown Los Angeles, according to the U.S. Geological Survey. The USGS noted that the earthquake was felt widely across the region, leading to rampant social media posting about the so-called “hurriquake.”
East of Los Angeles, roads in the San Bernardino Mountains were blocked by mud and debris flows, per the AP, and parts of the I-10 freeway near Palm Springs and the Pacific Coast Highway in Huntington Beach were also reported as flooded. Observation stations throughout Los Angeles reported similar rain totals to Santa Monica, with the center of Hilary passing through downtown Los Angeles at 7 p.m. Sunday evening.
“Los Angeles was tested but we came through it, and we came through it with minimal impacts considering what we endured,” Los Angeles City Council President Paul Krekorian told the AP.