In the U.S. and Canada, a five-category estimation of the avalanche danger: Low, Moderate, Considerable, High and Extreme. Avalanche forecasters use the Danger Scale to communicate travel advice, the likelihood of avalanches, and the size and distribution of avalanches. The ratings are used in backcountry avalanche bulletins accessed via the web, email, or a voice recording, and are usually accompanied by a more detailed discussion of the avalanche danger. Additional Terms: Anchors Hard Slab Avalanche Slide Aspect High Danger Sluff Avalanche High Marking Snowpit Avalanche Path Isothermal Soft Slab Avalanche Avalanche Transceiver Layer, Snow Stability Bed Surface Leeward Stability Test Collapse Loading Starting Zone Concave Slope Loose Snow Avalanche Stepping Down Considerable Danger Low Avalanche Hazard Sun Crust Convex Slope Melt-Freeze Snow Surface Hoar Cornice Metamorphism, Snow Sympathetic Trigger Corn Snow Moderate Danger Temperature Gradient Couloir Persistent Weak Layers Terrain Trap Cross Loading Point-Release Track Crown Face Probe Trigger Danger Ratings Propagation Trigger Point Deep Slab Avalanche Rain Crust Upside-Down Storm Density, Snow Remote Trigger Weak Layer Depth Hoar Rime Weak Interface Dry Snow Avalanche Runout Zone Wet Snow Avalanche Extreme Danger Sastrugi Windward Faceted Snow Settlement Wind Loading Fracture Ski or Slope Cut Wind Slab Glide Skinning, Skin Track Whumpf Graupel Slab   This glossary contains excerpts from "STAYING ALIVE IN AVALANCHE TERRAIN", by Bruce Tremper -