The snowpack has poor structure. At the higher elevations large slab avalanches could be triggered by humans on steep slopes. On Wednesday afternoon a snowmobiler died in an avalanche on the south side of Mt. Leidy. This accident occurred on an east-northeast aspect at an elevation of 9,500 feet. The rider was at the base of a steep slope when the avalanche released and buried him beneath six feet of avalanche debris. This soft slab avalanche was 2 to 3 feet deep, failed on faceted snow and propagated onto adjacent terrain features. Avalanches are unlikely below an elevation of 7,500 feet.
On steep slopes with poor snow structure humans could trigger slab avalanches up to three feet in depth. In these areas recent new snow lies upon a base of weak sugary (faceted) snow. In areas with weak snowpack persons who step off of their sled or skis will sink to the ground.
( Discussion is generated from the previous day's afternoon forecast. )Snowfall will decrease overnight. Skies will be mostly sunny on Friday with temperatures in the 20s and light northerly winds. In areas with poor snow structure unstable snow exists on steep slopes. In these locations recent new snow lies upon a base of well-developed faceted snow. These conditions can be found at the lower elevations and at higher elevations where the snowpack is still fairly shallow. In areas with a deeper snowpack buried persistent weak layers could still be a problem on some steep terrain features. Large slab avalanches with depths to three feet can be triggered by humans on some steep slopes. The general avalanche hazard is moderate. Evaluate terrain and the snowpack carefully.
