Flash Flood — Niobrara, Wyoming

2015-06-04 · near Van Tassell, Niobrara, Wyoming

Event narrative

As much as eight inches of rain fell from slow moving thunderstorms across south and southeast Niobrara County during the predawn hours, which resulted in widespread flash flooding. Excessive runoff upstream into the Niobrara River and nearby creeks caused them to overflow their banks. Law enforcement officials evacuated residents of Lusk as well as those living along the Niobrara River downstream to Van Tassel several hours in advance of the flood wave. The worst damage occurred in Lusk where 20 to 30 homes and 15 to 20 businesses were destroyed. Flood waters and debris rushed down Main Street in Lusk, swamped four blocks, and shut down the town's water supply. The US Highway 85 bridge on the north side of Lusk collapsed onto the railroad tracks below. Flash flooding closed a 20-mile stretch of US Highway 20 from Lusk to the Nebraska border, US Highway 85 from Lusk to the Goshen County line, and a 35-mile stretch of Highway 270 from Manville north to Lance Creek. WYDOT closed traffic into and out of Lusk, except for residents and emergency responders. Various state agencies, including the Red Cross and Wyoming National Guard, assisted in the flood cleanup efforts. A local command center was established at the Lusk Fairgrounds with water, food and shelter. The governor declared a state of emergency for Niobrara County. Fortunately, there were no injuries or fatalities.

Wider weather episode

Thunderstorms across much of southeast Wyoming produced widespread large hail as well as some flash flooding from torrential rainfall. The worst flooding occurred during the predawn hours across southern Niobrara County from Manville to Lusk to Van Tassel.

View location on OpenStreetMap → (42.6800, -104.0500)

Source: NOAA Storm Events Database, event_id 589431. Narrative written by the NWS forecast office that issued the report.