Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 3
On slopes facing west, north, through east, it is likely you can trigger an avalanche up to three feet deep and hundreds of feet wide, failing on a widespread persistent weak layer (PWL). In the video below, Trent describes the snowpack structure where this PWL exists. Nearly 60 avalanches failing on this PWL have been reported to the UAC, with two fatalities and other riders sustaining serious injuries, including someone in critical condition at the hospital. Many families and friends of these victims, including those performing search and rescue work, have been deeply affected by these tragedies.
The safest strategy to avoid being caught in one of these large avalanches is to avoid terrain 30° and steeper on slopes facing the north half of the compass. Avalanches can be triggered remotely (from a distance) on lower-angled terrain, including from below.
