First Rain of the Season: Tracking August Tropical Storms

A rain gauge should be mounted six feet or higher and not be near any buildings to capture an accurate measurement.

Hurricane Hilary which was classified as a Category 4 hurricane on August 16, was downgraded to a tropical storm early August 20. The storm provided steady rain to Pacific Palisades.

Pacific Palisades rainfall season starts on July 1 and runs through June 30 and the annual average in Pacific Palisades is 13.78 inches of rain. At the rain gauge off Radcliffe Avenue, 3.5 inches of rain was captured between August 20-21. A rain gauge in the Highlands captured 4.5 inches of rain over the same time period.

School was called off today, August 21. In the late afternoon on Sunday, August 20,  Los Angeles Unified School District put out a statement: “We are expected to experience the peak of this storm at midnight, which does not afford enough time for our staff to adequately inspect our facilities.”

The statement also cited winds that were forecast “which may adversely impact our transportation network and system, putting students and employees at risk.”

According to FOX Weather, this was the first time that there has ever been measurable rainfall recorded on August 21, with records dating back to 1877. And another source said this was the first tropical storm to hit Southern California in 84 years.

That may be incorrect according to “A History of Significant Weather Events in Southern California,” complied by the U.S. Government. To see heat, cold, storm, wind and rain events, visit:click here.

Looking only for August tropical storms, six, not counting the most recent one were listed: Diane (1972), “across Southern California. 2.1 inches of rain fell in Lucerne Valley in less than one hour. 0.38” fell in Riverside, and 0.31” in Big Bear Lake. And flash floods covered Interstate 15.”

Doreen (1977) most areas received at least 2 inches of rain, and “four dead and $25 million in damage in Southern California. Debris flows and flooding from Henderson Canyon into Borrego Springs De Anza neighborhood, damaging 100 homes. Mud flows up to 5’ deep. Flooded roads in desert areas. Floods and crop damage at the Salton Sea.”

Ismael (1983) “Flash flooding trapped two in their cars with water up to the windows, several homes were also damaged. Floods isolated 50,000 people in Palm Springs. Thunderstorms also knocked out power to 80,000 people in the Inland Empire.”

Hilary (1993) “Rain and thunderstorms produced 3-4” in two hours from heavy thunderstorms in the San Bernardino Mountains, Morongo Valley, and Desert Hot Springs.”

Dean (2007) “a former category 5 hurricane in the Pacific, produced thunderstorms and heavy rain in the morning, then again in the afternoon. In Escondido nearly 2 inches fell in less than 90 minutes in the morning.”

Ivo (2013)” brings severe thunderstorms. One storm dropped six inches of rain by the Salton Sea.”

Tropical storms were also common in September and in 1939, four tropical storms were recorded and “45 killed in floods all over Southern California, and 48 more at sea. In response, the weather bureau established a forecast office for Southern California, which began operations in February 1940.”

The tropical storms in September 1939 killed 93 people. The shot was taken at Long Beach.


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