The National Weather Service (NWS) issued urgent flash flood warnings and severe thunderstorm warnings for parts of the desert in southern Nevada, western Arizona, and southern California on Thursday.
“We had a thunderstorm develop to the south of Las Vegas and it’s just been sitting there dumping some pretty heavy rain at times, which triggered us to issue a flash flood warning, because rainfall that heavy, especially when it’s not moving, can lead to flash flooding and water flowing through the washes,” NWS meteorologist Ashley Nickerson, who works at the Las Vegas office, told Newsweek.
Why It Matters
The warnings arrived as heavy rain, brought on by a rare summer convergence of storm systems, threatened typically arid regions of Nevada. The surge in moisture followed less than a week after remnants from Tropical Storm Alvin affected the Southwest, raising concerns among meteorologists that similar tropical influences could bring more unusual rainfall in the region during the ongoing hurricane season.
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The timing was significant for local residents and infrastructure, as Las Vegas and neighboring communities are unaccustomed to widespread rainfall outside of the annual monsoon season, which generally begins later in the summer. Warnings from the NWS highlighted the immediate risk to life and property as roads, low-lying areas, and washes became rapidly inundated.
What To Know
No specific rainfall amounts have come in, but radar has indicated rainfall rates of up to 1 inch in the past half hour.
There are no climate sites in the affected areas that record rainfall, but Nickerson said Las Vegas typically sees no rainfall during the first week of June, making this an unusual event.
The NWS flash flood warning for southern Nevada will remain in effect through Wednesday at 4 PDT, with alerts extending to the Las Vegas Valley, Lake Mead, southwestern Clark County, and nearby recreation and conservation areas.
San Bernadino County in southern California is under the same watch as Nevada.
West Central Mohave County in northwestern Arizona falls under a similar alert, which lasts until 4:15 local time.
Meteorologists warned of possible sudden rises in washes, flooded intersections, and the movement of debris across roadways as a result of intense rainfall.
The severe thunderstorm warning for the Las Vegas region outlined the additional threat of damaging wind gusts and frequent lightning strikes, urging residents and travelers to seek shelter indoors and avoid flooded roadways.
Authorities noted the presence of accumulating dirt and debris on roads, compounding the danger of flash floods and diminishing driving visibility. The Mojave National Preserve and other park officials have also urged visitors to be aware of local wildlife that may become active following the rainfall, like desert tortoises.
Residents and travelers are being advised to heed all warnings, monitor local weather channels, and avoid streams, washes, and low-lying areas during active flood alerts.
What People Are Saying
Nickerson told Newsweek: “This is really abnormal for us. June is not our wet month. This type of pattern where there’s a lot of moisture in place and thunderstorms developing is more typical of our monsoon season, which doesn’t start until July.”
NWS Las Vegas in a flash flooding warning: “Life-threatening flash flooding of low-water crossings, creeks, normally dry washes and roads. Turn around, don’t drown when encountering flooded roads. Most flood deaths occur in vehicles.”
What Happens Next
Thunderstorms are expected throughout the rest of the day on Wednesday, with isolated showers and some thunderstorms expected tomorrow as well. This weekend, dry heat is expected to return.
