The addition of weight on top of a snowpack, usually from precipitation, wind drifting, or a person.
Loading from Wind:

As we know, snow does not like rapid changes, especially a rapid increase in weight piled on top of a buried weak layer. By far, the quickest way to load snow onto a slope is from wind drifting. Wind can deposit snow ten times more rapidly than snow falling out of the sky.

Wind erodes snow from the windward (upwind) side of an obstacle and deposits snow on the leeward (downwind) side. Deposited snow looks smooth and rounded. You should always beware of recent deposits of wind drifted snow on steep slopes.

Loading from Snow or Rain:

The second fastest way to load a buried weak layer is through new snow or rain. Rapidly-added weight almost always means rapidly-rising avalanche danger. Remember that more precipitation usually falls at higher elevations than lower elevations and more on the windward sides of mountain ranges than the leeward sides (with the exception of wind drifting near the ridges).

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