A flash flood watch is in effect through Sunday, May 8. A flash flood watch has been issued from the National Weather Service in Riverton for portions of southwest Wyoming including south Lincoln county, Salt River and Wyoming Ranges and Star Valley.
This watch is expected to last through Sunday afternoon at 6 p.m. Two to three inches of rain has been received since Friday evening. An additional two to four inches is expected.
Heavy rain lasting through saturday afternoon may cause flooding of small streams and creeks over the Owl Creek and Bridger mountains along the Lander foothills, across portions of natrona county, the southern end of the Wind River Basin, Sweetwater, Lincoln and Sublette counties.
Rainfall will continue and increase across the southern half of the Bighorn Basin, into the Wind River basin and the Lander foothills, and across Natrona county, Sweetwater, Lincoln and Sublette counties; continuing through saturday night with rainfall heavy at times, then tapering off some on sunday.
Thunderstorms have already put down an inch or more over the city of casper. Sublette and Lincoln counties have received one to three inches or rain and one to two inches across Sweetwater counties. Total rainfall amounts through Sunday morning are forecasted to be three to four inches with some areas along the Lander foothills and eastern Wind River basin and mountains receiving up to six inches. Snow levels with this event will continue to drop to around 8500 feet Saturday morning, then bounce between 8500 and 9500 feet through Sunday morning.
Rainfall and snowmelt runoff will combine forces this morning to cause rapid rises of small streams and creeks along the lander foothills as well along the lower elevations of the southern wind river basin and through wind river canyon. Small streams and creeks are expected to run at high levels through sunday morning. Additionally, mud slides and rock fall will be an issue in canyon areas, especially through wind river canyon. All streams across Sweetwater, Lincoln and Sublette counties can expect flooding.