Data Class Information category Observations Made Red Flag Values Your Observations

Precipitation Type Rain/heavy wet snow
Intensity >3 cm / hr
Accumulation >30 cm/ 12 hr
Wind Speed Strong enough to move snow
Direction Moving snow onto/across route
Duration Long
Temperature Current ≥ 0◦c
Maximum ≥ 0◦c
Minimum ≥ 0◦c
Trends Rapid change
Solar radiation Cloud cover Allowing a lot/ intensifying
Intensity Strong
Duration Long

Snow Cover Height < 1.5m
Strength Weak
Variability High
Layers Strength Strong over Weak
Temperature Near/= 0◦c
Grain Characteristics Large, loosely packed, angular grains
Bonding Strength Compression test ≤20
Rutschblock ≤4

Plane Characteristics Smooth, Clean
Failure Layer Large, loosely packed, angular grains
Whumping Initiation Natural/Human Trigger
Propagation Far (>3m)
Extent Widespread
Avalanche Activity

When Current Observed
Recent <24 hr (Maritime climate)
lt;48 hr (Continental)

Past If condition still exists
Where Area Widespread
Terrain Type Similar to route
Terrain Traps Angle/Aspect Traps exist where avalanches are running
What Natural Triggers All Natural Triggers
Human Triggers All Human Triggers
How Destructive Potential ≥ Class 2
Propagation Wide fracture lines running far
Failure Layer Large, loosely packed, angular grains