Rivers begin rising with warm-up

A stretch of beautiful weather is on tap for Northwest Montana this week with the forecast showing some of the warmest temperatures of the season.

According to the National Weather Service in Missoula, highs in the Northern Rockies could climb into the mid-70s or even low-80s beginning Thursday with nothing but blue sky and sunshine overhead.

The dramatic warming trend will cause the region’s historically deep mountain snowpack to begin to recede, leading to an increase in river and stream flows through the weekend. There is no flooding expected at this time, but the National Weather Service is predicting mainstem rivers will rise 2 to 5 feet by Sunday.

“This will be a big change for those who use the rivers and streams,” the Weather Service noted in its Tuesday forecast discussion.

River recreationists should be on the lookout for an increasing amount of debris in the water and take note of the risk of hypothermia, the Weather Service warned. The water temperature of the Flathead River at Columbia Falls was at 39 degrees Tuesday morning, and the river was flowing at about 23,600 cubic feet per second.

The Flathead Basin’s snowpack remains about 167 percent of average. A weather station on Flattop Mountain in Glacier National Park shows 138 inches of settled snow.

This week’s warm-up will come to an abrupt end Sunday, with high temperatures dipping back into the 50s. Mountain snow and valley rain is likely.

“It will feel like a big cool down after this week,” the Weather Service noted.