With a significant warming trend expected this week, the National Weather Service is forecasting increased flooding potential for some Western Montana rivers, including the Flathead River.

The Flathead River at Columbia Falls could reach or exceed flood stage by Thursday or Friday, but other rivers such as the Whitefish and Stillwater Rivers are no longer expected to exceed flood stage without a major rain event, meteorologist Bruce Bauck said during a conference call on Monday.

The Whitefish River has been running within a couple of inches of flood stage while the Stillwater has been more than half a foot below flood stage.

Temperatures in Kalispell are expected to reach the upper 70s by today, the 80s by Wednesday and remain in the lower 70s or upper 60s through the rest of the week.

“By Wednesday, we should see the warmest temperatures of the spring so far,” Bauck said.

Cooler weather over the last month has allowed a gradual snowmelt throughout much of the region, and the flood threat on the Yaak, Thompson, Fisher and Bitterroot rivers has been substantially reduced.

“We’re actually chipping away at the snowpack,” Bauck said. “But in the Flathead, the snowpack is huge.”

The Noisy Basin automated snow gauge on the Swan Mountain Range has lost some water over the last week, but it remains 20 inches above the record and more than 49 inches above normal for this time of year.

Noisy Basin, at an elevation of 6,040 feet, still has 118 inches of snow containing 62.5 inches of water. Normally at this time of year the site has 13 inches of water in the snowpack.

Snow-water content at the Moss Peak site in the Mission Mountains similarly is 20 inches above record level and 50 inches above normal.

At Moss Peak, the 122 inches of snow contain 64.5 inches of water. The Moss Peak measuring site is at an elevation of 6,780 feet.

Overall, high-elevation snow measuring sites in the Flathead River Basin have water content that is 424 percent of average.

Even with this week’s warm spell, Bauck stressed that the resulting flows on rivers such as the Flathead may not be the peak runoff flows for this year because the snowpack is so far above average.

“We’re just in new territory, folks,” Bauck said.