Avalanches

thumb|upright=1.25|A powder snow avalanche in the Himalayas near [[Mount Everest]] An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can be triggered spontaneously, by factors such as increased precipitation or snowpack weakening, or by external means such as humans, other animals, and earthquakes. Primarily composed of flowing snow and air, large avalanches have the capability to capture and move ice, rocks, and trees.

Huascarán (, ; Quechua: Waskaran), Nevado Huascarán or Mataraju is a mountain located in Yungay Province, Ancash Department, Peru. It is situated in the Cordillera Blanca range of the western Andes. The southern summit of Huascarán (), which reaches , is the highest point in Peru, the northern Andes (north of Lake Titicaca), and in all of the Earth's tropics. It is the fourth highest mountain in South America after Aconcagua, Ojos del Salado, and Monte Pissis. Huascarán is ranked 25th by topographic isolation.

thumb|Digging a snowpit on Taku Glacier, in Alaska to measure snowpack depth and density Snowpack is an accumulation of snow that compresses with time and melts seasonally, often at high elevation or high latitude. Snowpacks are an important water resource that feed streams and rivers as they melt, sometimes leading to flooding. Snowpacks provide water to down-slope communities for drinking and agriculture. High-latitude or high-elevation snowpacks contribute mass to glaciers in their accumulation zones, where annual snow deposition exceeds annual melting.