SANDPOINT — The U.S. Forest Service is warning backcountry visitors of avalanche danger in the Idaho Panhandle National Forests.

The agency released an advisory Friday which indicated that avalanche conditions for the entire forest area are rated as “considerable” on slope aspects above 30 degrees in elevations above 5,000 feet. Conditions on 30-degree slopes below 5,000 feet are rated “moderate.”

“Natural avalanches are unlikely, human triggered avalanches are possible,” Kevin Davis of the IPNF Avalanche Center said in the advisory.

In a snowpack assessment, Davis said natural avalanches were occurring on Thursday on steep northerly terrain as the snowpack adjusts to heavy loading from wet snow and rain.

Explosive control work at Schweitzer and Silver mountain resorts yielded results on many terrain features and slides were running to near ground in places on the very faceted, sugary snow. In the Selkirk Mountains, Avalanche Center officials discovered a significant weak layer midpack at a pronounced layer of surface hoar.

“The surface snow is highly variable from a slight ice crust to hard wind slab to several inches of powder,” Davis’ report said.

Davis and another avalanche analyst reported that they were generating telltale “whumphing” on west aspects in the Selkirks near Schweitzer on Thursday. Natural avalanche activity was most pronounced on northerly aspects.

“Be aware of shallow snowpack and stay away since it is very weak and stay away from steep terrain surrounded by shallow snow,” said Davis.