Record rain but no flooding yet on Flathead

Record precipitation was recorded in the Flathead Valley and at higher elevations Thursday, but cool weather is likely to halt snow melt and keep local rivers in check for now, according to the National Weather Service in Missoula.

The bad news is that record snowpack at higher elevations will have to melt eventually, creating a potential for serious flooding when higher temperatures arrive in June, Weather Service Meteorologist Bruce Bauck said.

Thursday’s weather front brought more snow and added to an already-ominous snowpack in the Flathead River Basin.

At the Noisy Basin snow-measuring site east of the Flathead Valley, the snow depth increased 15 inches to a total of 144 inches from Thursday to Friday.

“This is by far the record,” Bauck said.

The snow-water content at Noisy Basin, elevation 6,040 feet, grew from 66.1 to 68.7 inches. That means nearly 6 feet of water poised to flow downslope when the snow melts.

Similarly, the Flattop Mountain site at 6,300 feet in Glacier National Park received 8 inches of new snow. Snow depth on Flattop is 138 inches with 60.8 inches of water in the snowpack.

“The potential for a very substantial runoff in June is there,” Bauck said.

In the valley, a record rainfall of .73 inches was measured at Glacier Park International Airport on Thursday.

The previous record for May 26 was .61 inches set in 1942.

But lower temperatures have kept most rivers from reaching flood stage, a trend that is likely to continue through at least early next week, according to the Weather Service.

River hydrographs show the Yaak River near Troy dropping below a flood stage of eight feet today and remaining below or at flood level for the next week.

The Flathead River, which measured at about 13 feet at the Columbia Falls gauge on Friday afternoon, is expected to stay at that level before potentially reaching flood stage of 14 feet in a week.

Likewise, most branches of the Flathead River are expected to remain high but slightly below flood stage over the next several days, according to the Weather Service.

A flooding advisory remains in effect in Flathead, Lincoln and Sanders counties for small streams that have swelled with recent rain, according to the Weather Service.

Bauck said rain forecast for the Flathead Valley this weekend likely will not have much impact on river levels.

Flathead Lake, which is at risk of surpassing full pool, was at an elevation of 2,890.22 feet on Friday. Full pool is 2,893 feet.

Water was flowing into the lake at a rate of 45,620 cubic feet per second on Friday. The outflow through Kerr Dam was 37,521 cfs.

The Army Corps of Engineers warned Thursday that the lake may overflow in early June.