The area where a trigger initiates an avalanche.
Trigger Point:

When weather events (wind, snow, rain or sun) stress the snowpack close to its breaking point, often just a small thump will initiate a fracture and cause the whole slope to shatter like a pane of glass. Since snow varies quite a bit from place to place, sometimes several people can cross the slope before one person finds the “trigger point.” .

Often the trigger point is a place where, 1) either the buried weak layer is especially weak, 2) the stress on the weak layer is especially great, or 3) the overlying slab is thinner or softer and a person can more easily tickle the buried weak layer, which initiates a fracture. For instance, In continental or intermountain snowpacks with faceted snow as the weak layer, often the trigger point is near shallow, rocky areas on the slope or near a ridge where the slab is thinner. On a recently wind loaded slope, the trigger point is often where a thick layer of wind drifted snow has overloaded a steep part of the slope.

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