National Weather Service in Riverton Warns of Ice Jam Flooding

The National Weather Service in Riverton is warning residents about potential ice jam flooding that could come as a result of rising temperatures.

March 05, 20212 min read

Ice Jam Moose Lodge
(Cowboy State Daily Staff)

The National Weather Service in Riverton is warning residents about potential ice jam flooding that could come as a result of rising temperatures.

“Spring is around the corner. Along with warming temperatures it is also the prime time for the breaking up of river ice which has the potential to form ice jams and related flooding events,” the office wrote in a post on social media. “Be Safe…Be Prepared.”

An ice jam develops when pieces of floating ice accumulate to obstruct the river flow. The water that’s held back behind the temporary dam could potentially cause flooding or flash flooding upstream.

If the obstruction breaks, there could be flash flooding downstream.

Ice jams in Wyoming are most common between mid-February through early April and are seen in most rivers, but especially in the Green, Wind and Big Horn River Basins.

According to the Casper Star-Tribune, there was an ice jam flood in the Big Horn Basin in 2017 which forced the evacuation of more than 100 homes and businesses, causing hundreds of thousands of dollars in damages.

Major flooding events in Wyoming are relatively rare, with the last occurring in 2011, according to the NWS, and causing $5 million in damages.