LOVELAND, Colo. — The Colorado Flood Threat Bulletin and National Weather Service on Wednesday warned of the potential for flash flooding on the Alexander Mountain Fire and Stone Canyon Fire burn scars.
The impact of a wildfire is not over once the flames are extinguished. Particularly when a fire burns on steep and variable terrain common in Colorado’s mountains and foothills, the risk of flash floods and debris flows in the surrounding area can be heightened for years.
"Obviously, with the thunderstorms, the predicted thunderstorms, there's potential for flash flooding," said Justin Whitesell, the chief of emergency services with the Larimer County Sheriff's Office.
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Whitesell told Denver7 his team was keeping a close eye on the incoming storm and the impacts it could have on the Alexander Mountain Fire burn scar.
"Every time in the summer, we're either dealing with fire or floods. And right now, it's the floods that we're dealing with, because we've had quite a bit of rain throughout the summer. And with the recent — or the past — fires, obviously increases the potential for flash flooding," he said. "We're keeping an eye on the weather and the thunderstorms coming through, and seeing if they're going to cause any issues for us."
He also told Denver7 if there's risk of a flash flood, his team is prepared to call deputies to the burn scar area.
"We monitor rain gauges out around the county," Whitesell said. "If we get significant amounts of rain falling anywhere from a half inch to an inch of rain, we do send deputies that are in the area, but also emergency services personnel to see if there's any concerns or potential issues with the water coming down."
After the Alexander Mountain Fire was contained, Larimer County officials sent drones to take a look at the area and note any potential concern areas.
"After the Alexander Mountain Fire, there's a particular drainage that flows down into the Big Thompson River, and that had a lot of potential [for flooding] with the severity of burn that we saw. We sent the drone teams up there to fly it and identify any potential impacts or any areas of concern," Whitesell said. "When they flew, they didn't identify anything that was of huge significance."
"Obviously, that could change just with the amount of debris that comes down, or if it releases a landslide of even a small proportion, could block the creek and cause more problems later on, if we get enough rain," Whitesell added.
Over in Boulder County, Mike Chard, the director for the Office of Disaster Management, told Denver7 he and his team had been closely monitoring weather radar and weren't too concerned about the incoming storm and the impact it could have on the Stone Canyon Fire burn scar.
"Well, with our burn scars here in Boulder County, a little bit different than the ones around us here," he said. "A lot of them are starting to get into that healing phase."
Chard told Denver7 the Stone Canyon Fire burn scar falls into that category.
"Specifically to Stone Canyon, that one has come back pretty good, so we're not overly worried about it from a real significant flash flood," Chard said. "We still keep an eye on it because it has gone through a recent burn activity. We want to keep an eye and make sure that we don't have any flash flooding with it."
"It's reacted really well. It's greened up. It's kind of come back after the fire a year later," Chard said of the Stone Canyon Fire burn scar.
When asked how the Stone Canyon Fire burn scar has been able to reach such a healing phase, Chard said there are multiple aspects.
"This particular one, it looked pretty good. It wasn't super high, intense heat on that burn scar, so we didn't see some of the hydrophobic soils that we saw and other burn scars," he said. "It also doesn't have the steep canyon effect that you see in some of these other burn scars. So you don't have 32 degrees more of an angle with the canyon sloping, so it changes a little bit of the flood dynamic."
