New flood outlook sees increased spring flooding in Wyoming

CHEYENNE (AP) — The potential for flooding from the mountain snowpack melting this spring and early summer has increased in parts of central and western Wyoming, according to the latest spring flood forecast.

Portions of the North and South Forks of the Shoshone River in northwest Wyoming have been added to the river basins where there is a moderate to high potential for flooding when the snowmelt gets underway in earnest in May and June, the National Weather Service said in its flood potential outlook released Tuesday.

Moderate to high potential for flooding remains in the Big and Little Wind River basins in central Wyoming, the Upper Green Basin and Snake River Basin.

National Weather Service hydrologist Jim Fahey in Riverton said additional snow over the last month in the Absaroka Mountains in northwest Wyoming raised the flood potential for the North and South Forks of the Shoshone River west and southwest of Cody.

“It’s showing some really high snowpack and snow water equivalent values,” Fahey said.

Accumulated snowpack at the 8,500- to 10,000-foot elevation in the Wind and Upper Green basins are 170 percent to 180 percent of median.

“There’ll be some flooding with the some of the areas, especially on the Green and the Wind basins because of the amount of pack we have to melt, but most other areas if we melt it at a steady pace we’re not going to see big problems,” Fahey said.

The situation can change drastically if rain falls during the runoff, he said.

“That’s where we really have high water and it could be significant,” Fahey said.

Elsewhere, the risk of spring flooding is low and low to moderate around the Big Horn Mountains in north-central Wyoming and in southeast Wyoming.

Currently, the low-level snowpack — below 7,500 feet elevation — is rapidly melting out in many areas of the state because of above normal temperatures over the last week, according to Lee Hackleman, water supply specialist with the Natural Resources Conservation Service.

As a result, a flood watch has been posted through Wednesday night for portions of northwest, southwest and west-central Wyoming, including Jackson, Afton, Alpine, Thayne, Pinedale, La Barge, Big Piney, Farson, Kemmerer and Cokeville.