ERTH 2415 Lecture 17: L17 - Snow Avalanches
27 Mar 2018
School
Department
Course
Professor
Document Summary
Snowpack: snowpack is composed of several layers with different characteristics, thickness, density, hardness, cohesion, strength, etc, formed under different weather conditions, properties can change over time. Snow crystals: new snow characterized by 6 sided crystals, diameter = 0. 5mm, aging crystals, more rounded, more densely packed, more cohesive. Depth hoar: formation, vapour from underlying soil deposits on snow crystals at the base of the snowpack. Hoar crystals grow: density of the lower layer of the snowpack decreases. Surface hoar: surface hoar forms on cold, clear nights, vapour from the atmosphere deposits on the surface of the snowpack. Weak layers: weak layers usually, less dense, more transparent than adjacent layers. Snow avalanches: avala - to descend, to go down in old french. Avalanche types: the two types of avalanches can happen in any kind of snow, point-release avalanche, slab avalanche, most often, type depends on cohesion, low-cohesion snow. Point-release avalanches: most often develop in low-cohesion snow.
