If smoke isn’t coming off the fire on Ensign Peak, how is it only 10% contained?

SALT LAKE CITY ( ABC4 ) — Over the weekend, smoke and flames rose above Ensign Peak as a wildfire burned in the northern foothills of Salt Lake City . Homes were evacuated, fire crews responded, and planes dumped blood-red fire retardant on the hillside.

As of Monday, the evacuation orders were lifted and little smoke could be seen coming off what’s been dubbed the “Sandhurst Fire.” Yet, according to Utah Fire Info , the blaze was only 10% contained. But what does that mean, exactly?

Sierra Hellstrom is the spokesperson for the Northern Utah Type 3 Incident Management Team, which is currently heading the response to the Sandhurst Fire. She said containment refers not to the interior of the fire — where flames might be active or smoldering — but to the perimeter and where the fire might move if weather conditions shift.

“We don’t call an area of the line contained until we have a high degree of confidence that the fire will not progress further past that line,” Hellstorm said.

The Sandhurst Fire grew quickly on Saturday night, making runs up the hillside and burning mostly cheatgrass. In response, crews dumped water and fire retardant on the areas around the fire in an effort to slow its spread and protect nearby homes and other structures.

Since then, firefighters have been working to cool the perimeter to make sure the fire doesn’t “spot,” or jump, over the containment lines, particularly as it burns under the large oak shrubs.

“Yesterday, we saw a few hotspots where smoke and heat was coming up from the understory of those taller brushes,” Hellstrom said. “It’s not visible to the public driving around … but that heat is underneath there, and if it catches the right wind or the right heat, it could blow or burn into the next canyon.”

The containment of a fire can be visualized on maps released by officials. Areas of the fire line marked in red are “uncontained” while the parts in black are “contained.” Fire officials get detailed maps, including thermal imaging, from aerial surveillance.

For the Sandhurst Fire, the flames didn’t spread much on Monday, moving only three acres, increasing the total acreage to 204. Hellstrom expects a significant increase in the containment percentage Monday night as the fire has held through days of hot and dry winds.

“We decide this with an abundance of caution,” Hellstrom explained. “We want people to get back in their homes as much as possible, we want to open those trails, but we want to make sure that we have a high degree of confidence that we’re not going to get them back into their homes only to evacuate them again.”

Roads near the Sandhurst Fire remain closed to non-residents. Additionally, trails for Ensign Peak, Tunnel Springs, and part of the Bonneville Shoreline Trail are also closed. Investigators initially believed the Sandhurst Fire was human-caused, but later said the cause was undetermined.

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