Atmospheric River Storm Slams into SoCal

Introduction to the Storm

An atmospheric river hit Los Angeles in the early hours of Tuesday morning, bringing with it scattered downpours, powerful winds and fears of flooding. Evacuation warnings have been issued in areas ravaged by January’s firestorm — including the burn scars from the Palisades fire, the Eaton fire in Altadena, the Hurst fire in Sylmar and the Sunset fire in the Hollywood Hills — which are at a high risk of debris flows.

Weather Warnings and Predictions

A flash flood watch is in effect for most of the county through Tuesday afternoon, with the heaviest rain predicted for Tuesday morning. The National Weather Service warned that the “rare and very potent storm system” could fuel mudslides, thunderstorms, hail, and gusty winds capable of knocking down trees and power lines.
Increased risk of strong/severe thunderstorms across SW California tonight/Tue morning, capable of local damaging wind gusts of 60 mph+ brief heavy downpours+small hail. Conditions are favorable for rotating storms, capable of isolated waterspouts/tornadoes. #LAWeather #cawx

Storm Impact and Preparations

The storm began in earnest Tuesday morning, dropping rain across Los Angeles and knocking down trees near Balboa Avenue and the 101 freeway, according to the National Weather Service. “If outdoors, consider seeking shelter inside a building,” the Weather Service warned in statement. “Torrential rainfall is also occurring with this storm and may lead to localized flooding. Do not drive your vehicle through flooded roadways.” Before arriving in Southern California, the wintry storm swept through Northern and Central California, where it dusted the Sierra with the season’s first major accumulation of snow, caused flight delays at San Francisco Airport, and generated a whirling column of air and mist over Monterey Bay.

Regional Effects and Precautions

In L.A. County, the weather service predicts total rainfall of 0.75 to 1.5 inches in coastal and valley areas and from 2 to 4 inches in foothill and mountain areas. The storm system will also cause regional temperatures to plunge several degrees below normal. Flash flood warnings are in effect for much of Ventura County, parts of northern Santa Barbara County and inland Orange County, with residents in burn scars also warned to be prepared for debris flows. “Peak rainfall rates of 0.33 to 0.66 inches per hour will be common, which should be enough to cause plenty of minor road issues and heavy traffic for the Tuesday morning commute,” the weather services stated in its Los Angeles-area forecast. “Rockslides in canyon roads are nearly certain.”

Preparation and Response Efforts

Topanga Canyon Boulevard between Pacific Coast Highway and Grand View Drive was closed from 10 p.m. Monday until 5 a.m. Tuesday due to the predicted storm. This 3.6-mile stretch of highway is an ongoing work zone due to damage from the Palisades fire and previous winter storms. City and county authorities worked to prepare vulnerable areas with sandbags on Monday, while law enforcement went door to door warning residents in burn scars about the risk of debris flows. The Los Angeles Fire Department, in coordination with the state Office of Emergency Services, pre-deployed a 22-member strike team, a 27-member hand crew, a six-member urban search-and-rescue team and a 16-member swift-water rescue team to respond to potential debris flows.

Conclusion

The atmospheric river storm slamming into Southern California brings significant risks of flooding, mudslides, and debris flows, especially in areas previously affected by wildfires. Residents are advised to take evacuation warnings seriously, prepare for possible power outages, and avoid traveling unless absolutely necessary. The storm is expected to clear out by Wednesday evening, with a return to Southern California’s typical mild climate by Thursday.

FAQs

• Q: What areas are under evacuation warnings?
  • A: Areas ravaged by January’s firestorm, including the burn scars from the Palisades fire, the Eaton fire in Altadena, the Hurst fire in Sylmar, and the Sunset fire in the Hollywood Hills.
• Q: How long will the flash flood watch be in effect?
  • A: Through Tuesday afternoon.
• Q: What is the predicted total rainfall in L.A. County?
  • A: 0.75 to 1.5 inches in coastal and valley areas and from 2 to 4 inches in foothill and mountain areas.
• Q: How can residents prepare and stay informed?
  • A: Residents can sign up for emergency alerts at NotifyLA.org and pay close attention to evacuation warnings and orders from local authorities.