Utah endured several hours of nasty air Wednesday as a windstorm all but clogged the state’s dust-detecting air monitors before the snow came.
One state Division of Air Quality pollution sensor in Herriman reported 900 micrograms of particulate matter Wednesday morning — the highest reading the device is capable of detecting, according to Bo Call, who oversees air quality monitoring in the state.
But unlike frigid and stagnant weather conditions that in recent weeks created inversions and trapped pollution over Utah’s population centers, this pattern was new. The air still looked soupy and gray, though. The dust storm, in fact, gave way to a light snowstorm, in what weather analysts said signaled inversion-free skies through year’s end and possibly beyond.
“This is not related to a strengthening inversion,” said Christine Kruse, a forecaster for the National Weather Service in Salt Lake City. “This is related to strong winds pushing things into the air.”
“If you’re seeing this much wind,” Kruse added, “inversion conditions are no longer in effect.”
The Herriman air monitor was detecting PM 10, a larger type of airborne particulate matter than PM 2.5, the tiny particles typically associated with atmospheric inversions on the Wasatch Front. The larger particles are not considered to be as dangerous as the smaller pollutants, which can travel deeper into human lungs. However, high levels of PM 10 can still irritate the respiratory system, especially in sensitive individuals, such as those with asthma.
The good news, Call said, is that dust storms are indicators of changing weather patterns — in other words, the end of a recent inversion that has held polluted air in place and plagued northern Utah for the past several days.
“It’s really more of a sandstorm, but it’s going to pass,” Call said Wednesday morning.
“With the winds changing direction, first it’s going to blow one direction and then it’s going to blow another direction, and at some point we will get some rain or snow, and that should put an end to it,” Call said of the inversion’s demise. “As soon as the front gets here, we will be done and will have nice clean air for a while.”
As though on cue, snows began to fall over the Salt Lake Valley in the early afternoon.
As of Wednesday morning, the inversion was effectively gone, leading the state Division of Air Quality to lift its temporary ban on burning wood.
But dramatic weather also causes a lot of wind, Call said, and dry conditions of late mean wind is picking up a lot of dust, causing an hourslong sandstorm over the Salt Lake City metro region.
From October to early December, the Salt Lake and Utah valleys received less than half as much rain and snow as normal, according to the Utah Climate and Water Report from the Natural Resources Conservation Service.
It could be some time before Utah sees another long-term inversion. Kruse said she anticipates another weak storm system to pass over the Wasatch Front on Saturday and another on Monday.
“The best news is that we’re sitting in a pattern where [storm] systems are keeping us from becoming heavily inverted,” Kruse said.
The long-term forecast at Utah State University’s Utah Climate Center anticipates that the next inversion might develop in mid-January, but the odds of it building are slight. The center’s inversion forecast predicts clear skies will last through February.