Burn scar floods are just one of the worries once Utah’s big spring runoff starts
If you head east out of Stockton, Utah, to the Oquirrh Mountains and Soldier Canyon, you’re likely to notice the burn scar of the Jacob City fire. Last July, 4,112 acres were blackened here. The rubble of torched tree limbs, piles of debris and dark soil leave a grim memory.
Even before the fire, Soldier Canyon was already prone to flooding. But now there’s a combination of burned-over terrain and Utah’s record snowpack — this side of the Oquirrhs are at 223% of average — leaving “a lot of water in our upper elevation and it's just waiting to come down," said Bucky Whitehouse, the emergency services director of Tooele County.
"We actually had three floods the prior year in 2021, and then we had the fire,” Whitehouse said. “And so we have a population of people who live in or around the area that are on edge."
One reason for the threat of flooding is a lack of vegetation left in the aftermath of the fire. When a wildfire like the Jacob City fire burns hot it leaves little to no vegetation on the mountain terrain, said Kayli Guild of the Utah Division of Forestry, Fire and State Lands, so the soil can’t absorb water.
"The hotter the fire is, the more [the] likelihood that that happens to the soil composition. So if you have a little bit of vegetation, you're better off."
Locations that are downhill and downstream from burned areas are highly susceptible to flash
flooding and debris flows, especially in and near steep terrain. Utah's Watershed Restoration Initiative wants to get aerial seeding done on the ground so that vegetation can grow to help prevent flooding.
But time may be running low.
Burn scar flooding, mudslides and debris flows are typically a summertime concern during heavy rain, according to the National Weather Service.
"If you think of our rain events during the wintertime, they're moderate," said Glen Merrill, a meteorologist for the National Weather Service of Salt Lake City. "Not to say that flooding can't happen during the snowmelt runoff season in these burn scar areas, it's just not as likely."
Given the epic snow, Utah isn't ruling out the possibility of spring flooding. It’s dependent on if the soil “is able to absorb anything or if it just comes down super hard, super fast" which would lead to problems, said Guild.
Taking all of this into account, Tooele County Emergency Management officials are already preparing for the worst.
"We've got everything in there from large berms, and stream embankments that have been fortified. And different things that are either put in or will be put in before the summer gets here when our highest risk times are,” Whitehouse said.
The effects of a wildfire burn scar can last anywhere from three to five years, Guild noted. Scars from other fires over the past few years remain a concern for wildland officials — including the 2021 Pack Creek fire near Moab and the Parley’s Canyon fireoutside of Park City, as well as the Meadow Creek fire in Millard County, which burned over 4,000 acres in 2019.
Whitehouse said a post-wildfire assessment of the Jacob City fire scar suggests that problems for Soldier Canyon could persist even longer.
"We're looking at about five to eight years worth of high-risk water flows coming out of that particular area," he said.
At this point, residents living near the Jacob City fire are at the mercy of Mother Nature.
The typical water flow season in Tooele County is from mid-April until July. Whitehouse encourages residents to use that time to make sure their property is prepared for any potential flood danger by obtaining sandbags and checking for low-lying areas that could be impacted by a flood.
"I want to make sure that people understand that if they live near active waterways for spring runoff, that they know the risks, they prep their properties, and then if the situation is warranted, that they go ahead and get flood insurance in order to help mitigate and then to protect themselves for any kind of potential flooding."