Mary Mosteller and her husband lived in their dream home only three weeks before Monday night’s flash flood filled their first floor with water, dirt and debris.
The water rose about five feet at the highest point, filled their garage and first-floor rooms and carried four motor vehicles and a few all-terrain vehicles downstream to the Hat Six Ranch east of Casper. By Tuesday morning, the water had receded and left behind a muddy mess.
“When we started building it we had the [Casper Mountain] fires,” Mosteller said. “Now we finished it and moved in and we have floods.”
Areas downstream of the Sheep Herder Hill Fire burn scar faced an extra risk of flooding. Rainfall that is normally absorbed is more likely to run off because burned soil lacks vegetation, according to the National Weather Service.
Brett McDonald, with the NWS Riverton Weather Forecast Office, said flash floods occurred east of Casper after the area received a half inch to three quarters of an inch of rain Monday night.
“When that amount of rain falls in less than an hour, more like a 20- to 30-minute window, that’s more than enough water to cause flooding on a burn scar area,” he said.
Emergency officials reported flooding on the east side of Casper about 8:40 p.m., according to the Riverton NWS. Water crossed Second Street and Hat Six Road near the Clear Fork of Muddy Creek, and there were reports of hail on the east side of the city.
The Mosteller home and ranch on Hat Six Road were close enough to the mountain and creek to be in the path of those flood waters. When the rain started, Mosteller said the water ran through the normal mountain runoff channels. But about 15 minutes later, a spout of black water rushed down the mountain toward their house.
“I just thought, ‘Oh my god, I’m going to be washed out with my house,” she said. “I’ve never felt anything like that before.”
Mosteller said she felt trapped as the debris-filled water encircled the house, pushing in one garage door and out another. At one point, the water briefly came up to the main door.
She and her husband watched from windows on the second floor, which acts as the main floor of their house, as the water rushed past for more than an hour.
Lt. Stewart Anderson, emergency management coordinator for Natrona County, waded through the leftover rock and mud on Tuesday to survey damage at Hat Six Ranch, where the Mosteller vehicles ended up.
Anderson said the area also lost power, which was restored by Tuesday. The flash flood damaged at least four homes and the area is still at risk of flooding if more rain falls.
“We’re just seeing what the weather will do the next few days,” he said.
The NWS forecast for today includes a chance of isolated thunderstorms, and the rest of the week will continue in a similar manner. Thursday through Saturday there is a chance of thunderstorms with a 20 percent chance of rain.
Jason Anglin, with the Riverton NWS office, said a combination of moisture coming from the southwest and low pressure systems moving through the region have increased the chance of afternoon thunderstorms.
“We’re just kind of in an active pattern,” he said.
A slight high pressure system will move through central Wyoming the next few days, although Anglin said it won’t eliminate the chance for storms, and another low pressure system will likely bring a wave of storms this weekend.
Reach city reporter Kelly Byer at 307-266-0639.