Las Vegas, Phoenix, Tucson and Albuquerque all sit inside the part of the Southwest where flood risk stays elevated on Thursday, Oct. 22, even as the heaviest threat slides out of California. Forecasters expect up to 3 inches of rain across parts of the Desert Southwest, with isolated spots possibly reaching 5 inches. Both numbers are forecasts, and they depend on how long thunderstorms keep forming over the same ground.
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Four metro areas across three states, Nevada, Arizona and New Mexico, share one storm system and one worry: desert soil and pavement that cannot absorb rain as fast as it arrives.
Four Desert Cities in the Thursday Flood Zone
The Weather Channel forecast by Jennifer Gray and Miriam Guthrie, published on Oct. 21 and updated that afternoon, says the greatest flood risk shifts out of California on Thursday but remains for Arizona, Nevada, New Mexico, Colorado and Utah, “including Las Vegas, Phoenix, Tucson, and Albuquerque.” The same piece describes a multiday flood threat stretching across seven states from California to Colorado, driven by tropical moisture, and says soils in the region are already saturated, which leaves less room to soak up additional rain.
Wednesday, Oct. 21, was the highest-risk day for much of Arizona and New Mexico, parts of Colorado and Utah, and Southern California, according to the same forecast. It cites the Weather Prediction Center for rainfall rates as high as 2 inches per hour, with storms training, meaning moving repeatedly over the same areas. Thursday therefore inherits ground that has already been wetted, and that sequence is what turns an ordinary downpour into runoff that fills washes, arroyos and city streets.
Near-Record October Moisture and What 3 Inches Means
Some forecast models show near-record October moisture over the region, and the Weather Channel cautions that rainfall could therefore end up above the current numbers. The 3-inch figure is already large for the desert. For perspective, National Weather Service Phoenix wrote up a September event in which 2 to 4 inches fell in two to three hours from northern Pinal County through northern Maricopa County, with rates of 1 to 2 inches per hour, flooded washes and impassable low-water crossings.
That September storm also drew multiple swift water rescues, including a Maricopa County Sheriff’s Office helicopter rescue of two people from a submerged vehicle at a low-water crossing on State Route 238, and it led the Weather Prediction Center to raise its Excessive Rainfall Outlook to a Moderate Risk, the first for the Phoenix forecast area since 2023. It is a local benchmark for how quickly rain on this scale can overwhelm normally dry channels.
AccuWeather, writing about the same system, describes a non-tropical storm carrying tropical moisture from the eastern Pacific and says heavy rain and flash flood risk peak on Wednesday and Thursday across Arizona, Utah, western Colorado and New Mexico, before the storm moves slowly through the Southwest and Rockies later in the week. Its meteorologist Kai Kerkow said the storm “will pull moisture from the tropics into the Southwest.”
NWS Las Vegas Flood Watch and Burn Scars
On the Nevada side of the region, a flood watch issued by the National Weather Service office in Las Vegas at 4:21 p.m. PDT on Oct. 21 covers the Northwest Plateau of northwest Arizona, including northern Mohave County, through Thursday afternoon. It warns that multiple rounds of showers and thunderstorms with heavy rain could create a growing flash flood threat where repeated downpours occur, with possible flooding of rivers, creeks, low-lying areas, urban areas and low-water crossings. The copy of the watch used here is a third-party mirror whose expiration time is internally inconsistent, so the office’s own text governs.
The forecast also flags debris flows and mudslides over recent burn scars, plus flash flooding in slot canyons and arroyos, and advises visitors to western national parks to check forecasts daily and watch for warnings. Burn scars are a particular concern because scorched ground sheds water almost like pavement, sending mud and rock downhill with little warning.
Severe Storms, First Snow and Where to Check
Thursday also carries a threat of isolated storms producing strong winds, hail and possibly a tornado across the Desert Southwest and Four Corners, with Arizona at the greatest risk again, according to the updated Weather Channel forecast. At higher elevations, parts of the Sierra and Rockies could see their first significant snow of the season, with widespread totals under 6 inches but isolated peaks possibly near a foot, and rain can change to snow quickly there.
Because these are forecasts, conditions can shift hour to hour. The Weather Prediction Center publishes its Excessive Rainfall Forecasts for the nation, and local National Weather Service offices issue the watches and warnings that matter for an individual street or canyon. A flood watch means conditions favor flooding; a warning means flooding is happening or imminent.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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