Which statement best describes factors influencing runout?

• A. They are determined solely by weather
• B. They are irrelevant to snowpack structure
• C. They include Mass, Transitions, Drop, and Roughness
• D. They depend only on wind speed

Answer: (C)

Runout is driven by how much energy the moving snow has and how that energy is dissipated as it interacts with the terrain. The mass of the avalanche sets the initial energy and momentum, so heavier masses tend to travel farther if not quickly dissipated. Transitions in the snowpack, such as weak layers or abrupt changes in strength, influence how the flow propagates and where it may break apart or slow down. The drop height from the starting point determines how much potential energy converts to kinetic energy, boosting the runout potential. Terrain roughness affects friction and how the surface either resists or channels the flow, altering how far the avalanche can travel before stopping. These factors together provide the most complete understanding of runout behavior. Weather conditions or wind speed alone don’t capture this complex interaction, and ignoring snowpack structure would miss important ways energy is stored and dissipated.