Weak faceted snow from storms in early and mid November are present on most aspects at the mid and upper elevations. This past week we slowly put about a foot of snow on top of this weak snowpack, with nearly an inch of water. The snowpack began to show signs of its fragility this week with widespread cracking and collapsing and several human-triggered avalanches. Over the past 12-18 hours, we quickly added around another foot of snow (or more), an inch of water, and threw in some strong winds at the mid and upper elevations. On Thursday, the fragile snowpack was predictably very reactive with six human-triggered avalanches reported. Most of these avalanches were triggered remotely, and some were quite large, up to 2' deep and a few hundred feet wide.

You are very likely to trigger an avalanche in terrain steeper than 30° that has the persistent weak layer of faceted snow buried underneath the storm snow. These avalanches can be triggered remotely and from below.

Several observations from Thursday indicated sensitive storm snow during periods of higher precipitation intensity (PI), especially later in the day. You may find sensitive storm slabs in areas that received the most snow (a foot or more) or in areas that also had some wind-drifting. Triggering an avalanche that initially fails in storm or wind-driven snow will likely break down more deeply into the weak faceted snow down 2'.