Avalanche character definition table

Definition

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 entrainment	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.

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