A steep gully in alpine terrain. In winter, a couloir is usually filled with snow bound by rocks on either side. Couloirs: Couloirs can help anchor snow to the slope, but create a serious hazard if an avalanche does occur. They also pose numerous challenges for snowpack evaluation and safe ascent and descent. Often the only reasonable route is climbing straight up the couloir, which can expose the entire group to avalanche danger for considerable periods of time. Sometimes couloirs can be approached from the top, but then knowing the snow conditions in the couloir itself becomes just an educated guess.   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 -