Many along the Wasatch Front noticed earlier this week they may have to stop by a car wash or clean their windows after finding a dirty film had covered anything outside.
The film, which resembles dirty rain droplets, is likely the result of dust from the West Desert filtering into the greater Wasatch Front. But how does that happen?
Hayden Mahan, a meteorologist with the National Weather Service (NWS) in Salt Lake City, said a cold front moved from the west and toward greater Salt Lake. The cold front included windy weather, with gusts reaching up to 60 mph Wednesday in some places. Along with the wind came particulate matter, Mahan said, which acts as a nucleus for precipitation to attach itself to.
“We had a lot of particulate matter and dust in the atmosphere, but we also had some precipitation falling,” Mahan said. “So had that precipitation not occurred, then the dust wouldn’t have been as apparent.”
He added the particulate matter doesn’t have to be dust, precipitation could also bond to things like smoke from wildfires.
On Tuesday, the NWS tweeted that a dust cloud was blowing toward the Wasatch Front, which had hindered visibility between Salt Lake and Provo. It is this same dust that Mahan said is likely responsible for the dirty raindrops left behind.
Mahan said this week’s dirty rain extended to as far north as Ogden and as far south as Nephi, but mainly impacted Salt Lake and Utah counties.
He added that this type of dirty rain and dust plumes is somewhat common for this time of year, saying this time last year it was more frequent. Mahan said he was somewhat surprised to see the dust plume kick up, especially considering how wet the winter has been.
“No matter how wet of a winter we’ve had, there’s still that possibility of kicking up loose materials and lofting them and sort of infecting them further east,” Mahan said.
