Rare Weather Phenomenon in Desert Sparks Early-Morning Warning

Las Vegas experienced a rare weather event early Wednesday morning when fog descended on the desert city overnight and prompted meteorologists to advise caution.

The fog formed after light rain fell on and off in Las Vegas on Tuesday, which created a cool and saturated air mass.

National Weather Service (NWS) meteorologist Chris Outler told Newsweek that "really light winds," combined with the cool, saturated air mass, promoted the fog development. The fog is expected to continue until around 9 a.m. Eastern time on Wednesday morning.

The NWS office in Las Vegas commented on the "unusual sight" and included pictures in its social media post about the fog.

"An [unusual] sight for our desert eyes, pockets of dense fog have formed throughout the #Vegas valley this morning. Beware of sudden reductions in visibility on local roadways," the office posted on X (formerly Twitter).

Outler said: "The reason it's so unusual for us [is] just because here in the desert it's so arid and so dry we don't normally have that kind of moisture around and we don't live near a moisture source where we would see that kind of thing."

Outler said the NWS never issued a dense fog advisory because the fog was sporadic, but visibility was reduced to a quarter-mile in some areas. NWS meteorologists typically issue a dense fog advisory when there's widespread fog that limits visibility to a quarter-mile or less.

Although unusual, fog occurs sporadically in Las Vegas once or twice a year, Outler said.

"What's less common is seeing that visibility reduction down into the Strip and the Harry Reid Airport," he said. "I've worked here for 10 years and can't recall the last time we've seen it get that low at Harry Reid Airport itself."

Photos and a video of the foggy weather were shared on social media on Wednesday morning.

"Dangerously thick fog limiting visibility along the 15 near Blue Diamond at 3:00 a.m. in Las Vegas in the wake of yesterday's rain," KTNV meteorologist Justin Bruce posted on X with a dashboard video from a car traveling down a foggy highway. "Fog is fairly rare in the desert. I'm concerned we'll have freeway problems as volume builds after 5:30 a.m. if it doesn't break up before then."

In a follow-up post, Bruce shared a bird's-eye view of the Las Vegas Strip, which was blanketed by the fog. A faint glow from the Strip was slightly visible through the fog in the image.

One meteorologist shared a graphic showing how the fog affected visibility. In North Las Vegas and Summerlin, it was reduced to less than a mile. In Centennial Hills, visibility was reduced to a quarter-mile.