Avalanche character definition table
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Identify the Avalanche Character(s) that best represents the avalanche problem(s) within the defined Location. When multiple characters exist, they should be prioritized in order of importance.
Character | Weak Layer / Interface |
Slab Property | Persistence | Weak Layer Location |
Propagation Potential |
Relative Size Potential |
Loose Dry | Various (no cohesion) |
None | Hours/days | Near the surface | Down slope entertainment | R1-2 |
Loose Wet | Various (no cohesion) |
None | Hours/days | Any level | Significant down slope entrainment | R1-3 |
Wind Slabs | DF, PP | 4F-K wind transported |
Hours/days | Upper pack | Terrain features | R1-3 |
Storm Slabs | PP, DF | F-P Soft-stiff |
Hours/days | In or just below storm snow | Path | R1-4 |
Wet Slabs | Various | 4F-P Wet grains |
Hours/days | Midpack to deep | Path | R1-5 (climax) |
Persistent Slabs | PWLs such as SH, FC, CR, FC/CR combo |
4F-P Stiff-hard |
Weeks/months | Upper to midpack | Path to adjacent path | R2-4 |
Deep Persistent Slabs | PWLs such as DH, FC, CR, FC/CR combo |
1F-K Hard |
Weeks/months | Deep or basal | Path to adjacent paths | R3-5 (climax) |
Cornice | ~ | ~ | Months with short peaks | ~ | ~ | ~ |
Comment | Typical failure plane | Typical kind of slab | Typical duration of instability | Relative to HS | Typical expectation | Typical range of size relative to path |
Source:
Statham, G., Haegeli, P., Birkeland, K. W., Greene, E., Israelson, C., Tremper, B., et al. (2010). A conceptual model of avalanche hazard. Paper presented at the International Snow Science Workshop, Lake Tahoe, CA.