The Flathead Avalanche Center reports a rash of close calls in the backcountry over the last week as dangerous avalanche conditions persist in Northwest Montana.

A special avalanche warning was issued Tuesday for slopes in the Whitefish, Swan and Flathead mountain ranges, and in Glacier National Park. Natural and human-triggered slides are very likely due to a weak layer in the snowpack that was buried by the recent snowstorm, the advisory said. The avalanche danger was rated “high” for all upper-elevation locations.

Slabs of snow could break 2 to 4 feet thick and release destructive and deadly amounts of debris. Avalanche forecasters in recent days have seen slides as wide as 1,000 feet.

“Any steep (greater than 25 to 30 degrees) slope that is shaded and leeward to the wind is likely to slide right now,” warned Guy Zoellner, a forecaster for the Flathead Avalanche Center. “Skiers outside the Whitefish Mountain Resort boundary observed buried surface hoar on southerly slopes. More wind loading and additional weight from new snow could possibly add another aspect to the already complicated environment. Couple this information together, and the places one can go to avoid triggering or being caught in an avalanche are limited.”

A number of slides have been reported to the avalanche center since a series of storms dumped nearly 2 feet of snow on the mountains last week.

Recent reports from popular backcountry areas beyond the boundary at Whitefish Mountain Resort indicate a touchy snowpack. Fresh signs of avalanches were seen in the Canyon Creek area and off Ghoulies Point, and one skier triggered a slide on the backside of Lodi, just a short hike above the T-Bar 2 terminal.

One report notes a slide on the Halfmoon snowfield east of Big Mountain that is visible from Whitefish. Three sets of ski tracks mark the skier’s right side of the open slope, with a sizable avalanche on the other and ski tracks emerging from the debris field.

“Continue very safe and intentional travel in the mountains,” Zoellner wrote in Tuesday’s forecast. “As uncomfortable as it is to submit an observation of a triggered avalanche or an incident involving someone being caught and/or carried, that information helps us pattern the snowpack and keep the community, as a whole, safe.”