Tornado Risk From Tropical Storm Rachel Highlighted for Southeastern California, Las Vegas, and Western Arizona, Though No Official Watch Has Been Issued
Southern California – As Tropical Storm Rachel approaches Southern California, attention is turning to an often-overlooked danger that can come with tropical systems: tornadoes. A private forecasting group has issued its own unofficial tornado watch covering the eastern half of Southern California, including Imperial, Riverside, and San Bernardino counties, along with Clark County, Nevada, home to Las Vegas. The unofficial alert runs from Saturday at 3 p.m. until Sunday at noon. It is important to note that this is not an official tornado watch from the National Weather Service or the Storm Prediction Center, which are the only agencies that issue official watches and warnings.
Why Tornadoes Are a Concern With Tropical Storms
Tornadoes are a well-known hazard with landfalling tropical systems. When a tropical storm or hurricane comes ashore, the area to the north and east of the center, often called the right-front quadrant, tends to have the strongest wind shear and spin in the lower atmosphere. Thunderstorms that develop in these outer rain bands can sometimes rotate and produce brief, fast-moving tornadoes.
These tornadoes are usually weaker and shorter-lived than the large tornadoes seen in the Plains, but they can still cause damage and often form with little warning.
Areas Highlighted in the Unofficial Outlook
The forecast area outlined by the private group stretches across a large triangle of the Desert Southwest. It includes communities in Imperial County near El Centro and the Mexicali border region, Riverside County including Cathedral City and the Coachella Valley, and San Bernardino County stretching into the Mojave Desert.
The outlined area also extends north to Las Vegas and east into western and central Arizona, including Kingman, Lake Havasu City, Parker, Blythe, Yuma, Prescott, Flagstaff, Payson, Phoenix, Maricopa, Globe, and down to Tucson.
If Rachel moves ashore near San Diego, as some forecasts suggest, these areas would sit on the north and east side of the storm, where tornado potential is usually highest.
Official Watches Come From the National Weather Service
Residents should rely on the National Weather Service and the Storm Prediction Center for official tornado watches and warnings. A tornado watch means conditions are favorable for tornadoes to develop, while a tornado warning means a tornado is occurring or imminent and people in the warned area should take shelter immediately.
Official alerts are sent through Wireless Emergency Alerts on cell phones, NOAA Weather Radio, and local TV and radio stations. Residents should make sure these alerts are turned on throughout the weekend.
Damaging Winds and Flooding Also a Threat
Tornadoes are only one of the possible hazards. Rachel is also expected to bring widespread rain, embedded thunderstorms, gusty winds, and a serious risk of flash flooding across Southern California and the Desert Southwest from Saturday night into Sunday.
Flash flooding is often the deadliest threat from tropical systems in the desert, where dry ground cannot absorb heavy rain quickly. Washes, canyons, and low-water crossings can fill with fast-moving water in minutes, even if the heaviest rain is falling miles away.
Rare Tropical Weather in the Southwest
Tropical storms reaching Southern California are rare, but they can bring significant impacts when they do. In August 2023, Tropical Storm Hilary brought record rain, flooding, and mudslides to parts of Southern California and the Desert Southwest. Forecasters are watching Rachel closely to see how strong it remains as it nears the coast.
How to Stay Safe
Residents across the region should have a plan in case a tornado warning is issued. The safest place during a tornado is an interior room on the lowest floor, away from windows, such as a bathroom, closet, or hallway. Mobile homes are especially vulnerable, so residents in mobile homes should identify a sturdier building nearby to go to if needed.
During heavy rain, never drive through flooded roads, and stay away from washes and riverbeds. Keep phones charged, have flashlights ready, and secure loose outdoor items that could be blown around by strong winds.
Stay Tuned to Official Sources
Conditions could change quickly as Rachel approaches. Residents should follow updates from the National Hurricane Center, their local National Weather Service office, and local emergency officials throughout the weekend.
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