All the rain that’s fallen on Utah in the past couple of days didn’t leave the state smelling fresh and clean — it left it smelling like a wet campfire.
There are a couple of reasons for that, according to the National Weather Service. First, the storm system brought the smoke with it.
And, second, smoke from summer wildfires is different than winter inversion pollution.
“It has a very similar impact in terms of visibility and kind of gross air quality, but they don’t work in the same way,” said David Church, lead meteorologist at the National Weather Service’s Salt Lake City office. “This is a different phenomenon.”
The smoke currently plaguing Utah is from fires in California, Oregon, Washington and British Columbia. “There’s been a very large number of very large wildfires across the West,” he said. “So there’s just an incredible amount of smoke swirling around.”
And the storm system that moved through Utah this week “picked up smoke on the way in,” he said. “This low pressure system is bringing us rain, but it also pulled smoke from a lot of different areas into one spot. And it’s sitting right on top of us right now.”
It doesn’t always happen that way.
“Sometimes if we get a cold front coming in from the right direction, it can bring in some clear air and it will clear out the smoke,” Church said. “But this one just has smoke wrapped into it from all different directions. So instead of being able to improve the air quality across the region, this is locally concentrating it.”
That’s weird to Utahns who equate storms with improved air quality.
“We’re conditioned to think — every time it rains, it’s going to clear out the inversion. That’s what happens in the wintertime,” Church said. “But that winter inversion acts very differently from smoke from wildfires in the summer.”
And winter storm systems aren’t full of smoke from wildfires in other states.
What Utahns know about escaping inversions also doesn’t apply now.
“We’re accustomed to thinking, ‘Oh, I want to get away from the gross air in the valley. I want to go up to the mountains and go skiing or go hiking or something and I can get away from it,’” Church said. “And wildfire smoke doesn’t function that way. It tends to be dispersed much more evenly throughout the atmosphere. And, actually, in some cases, it can even be worse as you go up in elevation.”
The air quality in Utah is expected to improve beginning Thursday afternoon, and get better over the next couple of days.
“We’re going to see this concentration [of smoke] start to dissipate as the storm system pulls away,” Church said. “It won’t completely clear out, but it won’t be this wet snow-campfire smell that we’ve had.”