Like an unwelcome houseguest, the smoke clogging the sky in Summit County showed up unannounced on a Friday and is planning to stay awhile, though it isn’t clear exactly how long.
According to the National Weather Service, the smoke is likely to linger until at least next week, when there is a chance that the prevailing winds will shift and bring clean air this way.
But a bit of good news could be coming at the end of the week, according to Monica Traphagan, a meteorologist with the National Weather Service in Salt Lake City.
Traphagan said that winds are expected to decrease as the week progresses, meaning less new smoke will be heading to Utah from the wildfires burning west of here.
It also means that higher elevations could be clearer than lower areas, possibly offering a chance for respite for those willing to seek high places.
“In the situation where we’re talking about, (with) lighter winds, smoke will linger more in the valleys than it will in the higher terrain,” Traphagan said, adding that it was similar to the wintertime cold-air inversions common in the Salt Lake Valley.
But Traphagan said it wouldn’t be until this weekend or early next week that the weather patterns could change enough to drive away the smoke. She said the prediction carried a low confidence level.
The smoke arrived seemingly all at once on Friday morning, pushing into the area on the back of a cold front that shifted the prevailing winds from a southerly flow to a westerly one.
Instead of bringing moisture from the south, which — despite flooding issues — was welcome in many parts of the drought-ridden state, the new westerly flows brought smoke from fires burning in northern California, Traphagan said.
That includes the Dixie Fire, which has grown to nearly 500,000 acres.
The smoke overtook relatively clear skies Friday morning, leaving familiar landmarks including PC Hill and the Park City Mountain Resort shaded in an eerie haze.
The front edge of the smoke system caused air meters to spike in the Park City area. The most robust network of air monitors locally is maintained by a company called Purple Air. Readings on the air quality index, which ranges from zero to 500 and above, spiked to the 380s on some Purple Air monitors midday Friday and remained elevated through Monday evening.
Readings above 150 are considered unhealthy, while readings above 100 are considered unhealthy for sensitive groups, including elderly people or those with respiratory difficulties.
Traphagan said the Purple Air network is useful for assessing overall trends in an area but indicated it is difficult to ascertain an individual monitor’s accuracy. The company sells monitors for a few hundred dollars to homeowners and governments alike, and the Summit County Health Department has installed monitors at several municipal buildings in the area.
The air quality in Summit County is not included in a database monitored by the Utah Department of Environmental Quality.
When air quality is threatened, health experts recommend staying indoors if possible and avoiding outdoor exercise.
According to Intermountain Healthcare, short-term exposure to particulate matter in the air — present in wildfire smoke — is associated with changes in heart rate variability and increases in blood pressure, asthma symptoms and the incidence of strokes.
Long-term effects of repeated or chronic exposure can result in conditions that may lead to increased incidence of strokes, Alzheimer’s disease and Parkinson’s disease.
Traphagan indicated the acutely poor air quality is unusual, even for an area that has struggled with air quality issues for decades.
“I’ve lived here for 16 years and it’s the worst I’ve seen,” she said.