Wet stuff: Rain, 30-50 inches of snow

'Deep moisture' to slam region

What's on tap for Memorial Day weekend?

Heavy rain across much of Northwest Montana and from 30 to 50 inches of snow along the Continental Divide into Glacier National Park.

National Weather Service forecasters said Thursday that an unusual weather front, delivering moisture from the Plains states, also will bring lower temperatures.

Snow above 6,000 feet is expected to effectively "shut off the runoff," meteorologist Peter Felsch said.

Area rivers, which have been approaching or exceeding flood stage in recent days, are expected to gradually drop off during the next few days.

"It's very unusual," Felsch said, "to have this magnitude of deep moisture coming from the Plains like this."

Over the Flathead Valley on Thursday, cloud cover oddly drifted to the west, the direction it typically comes from. Weather Service satellite imagery shows moisture moving from the east over the Continental Divide into the valley.

The overall weather event was expected to begin Thursday afternoon and gradually taper off by early Sunday.

Total snowfall is expected to range from 30 to 50 inches above 6,000 feet, Felsch said.

"We're mainly talking about Logan Pass and the higher peaks that will get the bulk of the big dump," he said, adding that rainfall could total 2 to 3 inches in the valleys.

Felsch said the heavy snow could increase avalanche danger in the park and the heavy pounding of rain at lower elevations could cause high flows in small streams or water accumulating in low-lying areas.

A flood watch will remain in effect for the West Glacier area through today because of the expected heavy rain. Temperatures are expected to return to normal, with highs in the 60s and lows in the 30s, by later next week.

"In the longer term, because of the heavy wet snow that's accumulating in higher terrain, West Glacier will be an area of first concern … that we will have to watch carefully in the coming weeks ahead," Felsch said.

While major rivers such as the Middle Fork and main stem of the Flathead River were below flood levels, smaller rivers were running high Thursday.

The Stillwater River in Kalispell was within half a foot of flood stage of 7.5 feet on Thursday afternoon and was predicted to crest at 7.21 feet late today or early Saturday.

The Swan River at Bigfork also was 6 inches away from its 6.5-foot flood stage and was expected to remain at that level into Sunday. The Bigfork Whitewater Festival kayak races are staged on the Swan River Saturday and Sunday.

Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com