Wildfire smoke hung thick in the air along the Wasatch Front last weekend and earlier this week; numerous wildfires in Idaho, Montana, Washington, California and Oregon continue to burn, causing smoky skies in Utah.
New research from the University of Utah suggests wildfire smoke plumes are getting higher and traveling further as a result. Co-author of the study, Research Assistant Professor Derek Mallia, said wildfires are getting bigger and more intense.
“And something that we had wanted to explore with this study was did this impact how that smoke was being lofted into the atmosphere? So was that smoke being lofted further up? So what we found in this study is that indeed, fires are getting taller, they're lofting smoke further up into the atmosphere,” Mallia said.
Harnessing wildfire data from the last 20 years, Mallia and his colleagues developed a computer model to predict plume heights. What they discovered was an upward trend over the past two decades.
“So if that smoke is being lofted further up it increases the likelihood that it'll get caught up in something like the Jet Stream. And so as a result of that, that smoke can be transported much further downwind. So instead of seeing smoke having local and regional impacts across the Western US, it is possible now that areas across the Eastern US might more frequently see smoke episodes,” Mallia said.
Mallia and his team suspect climate change and changes to forest management are resulting in bigger and hotter fires, and that this underlies the increasing trend in plume height.
“What happens is as the fire burns hotter, the amount of heat being emitted by the fire is much more concentrated. And so what that does is that allows the air to rise much more quickly, due to buoyancy. It's kind of like a hot air balloon, right? If the air is warmer within that hot air balloon, it's going to rise up much further, you kind of see the same thing with a fire smoke plume,” Mallia said.
He added that wildfire-initiated thunderstorms called pyrocumulonimbus clouds are becoming more frequent. These storms can also loft smoke higher into the air.
