With Storm Approaching, Residents Warned About Possible Burn Scar Debris Flows
Sep 28, 2018, 7:24 PM | Updated: 9:14 pm
WOODLAND HILLS, Utah – Emergency officials have warned people who live near the Pole Creek and Bald Mountain Fires to be careful as heavy rain next week could trigger debris flows.
Off the Pacific coast of Mexico, Hurricane Rosa has been forecasted to move toward the West over the next few days. What’s left of the storm could bring rains as heavy as a half-inch per 30 minutes in Utah County.
“That rain intensity, we feel, will bring a debris flow – and we do have many areas at risk,” said Brian McInerney, a hydrologist with the National Weather Service.
McInerney was part of a Burned Area Emergency Response team that flew over the area Friday, surveying the area. They try to figure out where post-fire risks could exist.
What he saw from the thousands of acres of burned earth in Utah County concerned him.
“When you look at the physics of a debris flow, it’s monstrous,” McInerney said.
The fires left charred trees and loose, unstable soil behind high in the mountains. McInerney said burned soil does not absorb water, instead sending it rushing down through the watershed. That water could pick up downed trees and mud as it rushes downhill. Communities at the base of canyons and drainages could be at risk.
“These things move very fast and they just take the point of where it’s going to go. It doesn’t matter if you put sandbags up. It doesn’t even matter if your house is there. We’ve had some that have gone through the back of the house and come out through the front of the house,” he said.
McInerney said people who live near the canyons and drainages should keep an eye on the storm as it rolls through. If the rain becomes heavy, he said those people should go somewhere else until the rain lightens up. He said people in vulnerable areas should also avoid basements during the storm.
“The debris flow comes down, fills the window wells up, breaks the window, slams the door shut, and fills up the room. Keep your kids out of the basement, watch the weather,” he said.