Millions across the Southwest face tornado threats, flooding and hail as a severe storm system blankets the region through Thursday, with officials already urging residents to take cover.
The National Weather Service issued Tornado Warnings around Flagstaff, Arizona, as a broad storm system moved in from the Pacific and began dumping heavy rain across the Southwest. Forecasters said the setup would last from Wednesday morning through Thursday, with flooding rains, hail and a real tornado risk for large stretches of the region.
Daily Mail reporting described millions of Americans under warning for a severe storm that could injure people outdoors, damage roofs and vehicles, and turn roads into deadly flood traps. The system was already producing flash flood alerts in southern Utah by Wednesday morning, and Severe Thunderstorm Warnings in Prescott, Arizona, less than 80 miles north of Phoenix, told residents to take cover immediately.
The fuel for the storm was a low-pressure area high in the atmosphere, pulling tropical moisture from the remnants of Hurricane Trudy off Mexico’s coast. Moist, unstable air and wind shear, winds changing speed and direction with height, set the stage for heavy downpours and severe thunderstorms.
AccuWeather warned that the biggest threat focused on Arizona, with supercells possible around Phoenix, Tucson and Flagstaff. Flood Watches covered Arizona, New Mexico, Utah and southwestern Colorado. Damaging wind gusts of 60 to 70 mph were in the forecast across those states, and worst-case scenarios from AccuWeather projected gusts up to 80 mph, the same strength as a Category 1 hurricane.
The National Weather Service did not mince words on outdoor risk and property damage.
"People and animals outdoors will be injured. Expect hail damage to roofs, siding, windows, and vehicles. Expect wind damage to roofs, siding, and trees."
That plain warning matches the kind of early-season alert pattern readers have seen when the National Weather Service issues frost advisories and other rapid-onset hazards across multiple states. The message is the same: when the service raises the flag, people outdoors and on the roads need to act.
NWS officials also said the threat of isolated tornadoes was not over and would expand through the day into Southern California and Utah. Flash floods remained possible across large portions of Arizona, Colorado, New Mexico and Utah.
A Flood Watch covered the Los Angeles area, where forecasters expected up to three inches of rain, heavy downpours, small hail and even tornado-like waterspouts off the coast, with a small chance of a brief tornado over land. Heavy rains were already falling at nearly an inch per hour in parts of Southern California.
AccuWeather Senior Meteorologist Adam Douty put a clear window on the worst of it for the coast.
"The timing of the heaviest rain in Southern California is expected to be from Wednesday evening to the first thing Thursday morning."
NWS Los Angeles posted a direct warning for Santa Barbara as rain rates climbed.
"Watch out Santa Barbara! The storm is coming in with a fury. Rain rates as high as 0.80 per hour have been reported. Please drive safely and consider delaying travel if at all possible."
A new flood advisory in the Los Angeles area repeated the standard life-saving rule for motorists.
"Turn around, don`t drown when encountering flooded roads. Most flood deaths occur in vehicles."
That driver warning is not abstract. Most flood deaths still happen when people drive into water they cannot judge. Common sense says delay the trip when the National Weather Service is already telling you the storm is arriving with fury.
Las Vegas was expected to get soaked again. Douty noted the city had already blown past a normal October before this system even finished its work.
"Las Vegas has already picked up nearly four times their historical average rainfall for October with 1.19 inches falling through Tuesday. This storm will only add to that departure from average."
Those AccuWeather updates land in the same lane as other seasonal forecast shifts readers track when an AccuWeather forecast flips the U.S. snow map and forces a fresh look at winter patterns. The point for households is practical: abnormal rain totals raise flood risk even in desert cities that look dry most of the year.
As the system pushed north through Thursday night, Nevada, Oregon, Wyoming and Idaho were expected to see thunderstorms and potential flash floods. The footprint stretched from Southern California and Arizona into the interior West, with Flagstaff under tornado warnings, Prescott under severe thunderstorm warnings, and Flood Watches layered across a multi-state swath.
The timeline was straightforward. The system was expected to start blanketing the Southwest with drenching downpours Wednesday morning. Southern California’s heaviest rain was timed for Wednesday evening into early Thursday. Heavy downpours and severe thunderstorms were expected to continue through Thursday, October 22, including in the Los Angeles area. By Thursday night the storm was forecast to move north into Nevada, Oregon, Wyoming and Idaho.
October 21 warnings already covered flooding rains and a tornado possibility in the Los Angeles area. Flash flood alerts hit southern Utah Wednesday morning. No confirmed injury or damage totals were reported in the available accounts, the public notices remained at the warning and forecast stage, which is exactly when people still have time to get off the road and secure loose outdoor gear.
Broader seasonal storm risk has been a running theme in recent outlooks, including a winter outlook that flags East Coast storm risks for millions. Different coasts, same duty for local officials and households: treat multi-day severe weather windows as real, not background noise.
Early-season NWS products have already shown how fast conditions can flip, from the first winter weather advisories posted across four states to this Southwest tornado and flood package. The agency’s job is the forecast and the warning. The public’s job is to act on it.
Historical winter patterns offer mixed clues year to year, as seen in reviews of past Super El Niño winters, but a live Tornado Warning and Flood Watch do not require a long debate. Hail, 60-to-70 mph gusts, and rain rates near an inch per hour are enough reason to stay off flooded roads and keep people and animals indoors until the cells pass.
When the National Weather Service and working meteorologists lay out tornado warnings, flood watches and near-hurricane wind gusts in plain English, the responsible response is not to wait for someone else to decide, it is to take cover, delay travel and keep out of the water.
