| What it is | Cohesionless snow releasing from a point |
| Shape | Fans out into a triangle |
| Usually | Smaller than slab avalanches |
| Still dangerous | Cliffs, terrain traps, when large/wet |
A loose-snow avalanche (also called a sluff or point-release avalanche) starts at or near a single point in cohesionless snow and fans out into a triangular shape as it gathers snow moving downhill. Usually smaller than slab avalanches, sluffs can still be dangerous by knocking a person off their feet, pushing them over cliffs, or burying them in terrain traps or when large and wet.
This is general educational information, not avalanche training.
Sluff vs slab
The point-release counterpart to the far deadlier slab avalanche; when warm and saturated it becomes a wet avalanche. A type of avalanche.
Frequently asked questions
What is a loose-snow avalanche?
A loose-snow avalanche, or sluff, begins at a single point in loose, cohesionless snow and fans outward and downhill into a triangular shape as it entrains more snow. Unlike a slab, there's no cohesive layer releasing at once — the snow simply lacks the bonding to stay in place and runs from the start point.
Are loose-snow avalanches dangerous?
They're usually smaller and less lethal than slab avalanches, but they can still be hazardous: a sluff can knock you off balance, sweep you into a terrain trap or over a cliff, or — when large or wet — bury you. Sluff management (skiing to the side of your sluff) is an important steep-skiing skill.
Loose-snow vs slab avalanche?
A loose-snow avalanche starts at a point in unconsolidated snow and fans out, typically smaller; a slab avalanche releases a whole cohesive layer over a weak layer along a crown line and is usually far more dangerous, causing most avalanche deaths. Recognizing which is possible depends on the snowpack and conditions.
Sources
- Avalanche types — Avalanche.org
- Loose vs slab — American Avalanche Association