Intense Storm Triggers Rare Flooding Concerns
The remains of Tropical Storm Hilary, which had been a Category 4 hurricane while active in the Pacific, delivered an unprecedented amount of rainfall to Southern California after hitting the Mexican coast. This resulted in the flooding of roads, as well as triggering mudslides and rockslides as it moved northward.
Although Hilary was anticipated to weaken by Monday, meteorologists cautioned that the storm’s precipitation had the potential to lead to extremely dangerous flooding throughout the southwestern United States. Even regions as far away as Idaho were alerted to the possibility of flooding due to the storm’s impact.
Before reaching land on Sunday in Baja California, Mexico, Hilary was downgraded to a tropical storm, and by early Monday morning, it had transformed into a post-tropical cyclone.
“We haven’t cleared the danger zone yet,” cautioned Brian Ferguson, the deputy director of the California Governor’s Office of Emergency Services, in an interview with CBS News on Monday. He stressed that the trailing part of this storm still has an impact, and there’s a possibility of mudslides occurring today due to the saturation of the ground.
Brian Ferguson informed that there were no reported fatalities in the state due to Hilary. He described the harm to homes and essential infrastructure as “extremely limited.”
While Hilary was sweeping through Southern California on Sunday, a 5.1 magnitude earthquake struck near Ojai, located northwest of Los Angeles as reported by the U.S. Geological Survey. Ferguson mentioned that the earthquake did not result in any significant injuries or damage.
Numerous regions were experiencing flooding, and there were multiple reports of rockslides and mudslides. The Los Angeles office of the National Weather Service conveyed via social media that by 3 a.m. PDT on Monday, nearly all daily rainfall records for the area had been shattered.
Hilary marked the first tropical storm to make landfall in Southern California in 84 years.
It deposited over half of the average annual precipitation on certain desert and mountainous regions, including Palm Springs, which accumulated nearly 3 inches of rainfall by Sunday evening. As a result of the storm, tens of thousands of individuals throughout Southern California were without electricity, and Palm Springs encountered a loss of 911 service on Sunday night, according to CBS News Los Angeles. The station reported that the outskirts of Hilary were still affecting the greater Los Angeles area, subjecting certain regions to heavy rainfall early on Monday morning.
The Weather Prediction Center of the National Weather Service indicated that flood watches were in effect for several areas, including Southern California, northwest Arizona, large portions of Nevada, southwest Utah, eastern Oregon, western and central Idaho, as well as southeast Washington. The issuance of a flood watch signifies the potential for flooding in these regions.
According to the center’s statement, “Hilary is anticipated to generate additional rainfall ranging from 1 to 3 inches across sections of southeast California and southern Nevada until Monday, with isolated accumulations possibly reaching up to 12 inches. Persistent instances of flash flooding and urban flooding are to be expected.”
Additionally, Oregon and Idaho were predicted to receive rainfall amounts ranging from 1 to 5 inches by Tuesday morning, leading to localized and potentially significant episodes of flash flooding, the center added.
Nevada’s concern lay in the dangerous flooding risk across the western Mojave Desert, a circumstance the Las Vegas office of the weather service deemed “exceedingly rare,” as stated on social media on Sunday.
CBS News Los Angeles reported substantial rain occurring in Southern California, particularly in Los Angeles and the surrounding counties.
As of 7 a.m. PDT, the Angeles National Forest’s Mount Wilson had recorded a total of over 8.5 inches of rainfall, marking the highest measurement documented by the Los Angeles office of the weather service. Beverly Hills registered 4.8 inches, while downtown Los Angeles accumulated nearly 3 inches of rainfall.
The National Weather Service alerted that Ventura County was undergoing life-threatening flooding, with San Bernardino, Riverside, and the adjacent mountainous areas at a heightened risk of flash floods. As a response, evacuation orders were issued in San Bernardino and Riverside Counties, and evacuation warnings were released in Orange County.
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