Melting snow after last week's storm could result in flooding over frozen ground in Natrona and Washakie counties in the coming week, according to the Riverton office of the National Weather Service.

"People should now begin to fortify any areas of their property that have flooded in the past due to snowmelt runoff," the Weather Service cautioned.

Temperatures will rise to the upper 30s for much of Natrona County, and to the upper 40s to middle 50s in the Bighorn Basin by Tuesday through Thursday, along with the chance of rain across western and southwestern Wyoming by Thursday afternoon.

As a result, snowmelt below 8,000 feet is expected to increase steadily during the same time.

That could cause "sheet flooding," which happens when snowmelt runoff flows over frozen ground and causes rapid flooding of low lying areas, basements and road crossings near bridges, according to the Weather Service.

Likewise, increased snowmelt runoff flowing across frozen rivers and creeks may
cause ice breakups, ice jams and rapid rises in river and creek levels.