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Avalanche. A mass of snow, ice, and rocks falling rapidly down a mountainside. Snow Pack. Layers of snow and ice built up over time. Incline. The slope of a mountain. Terrain. Surface features of an area of land. Slab Avalanche. When the snowpack breaks away from the slope in sections.
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Avalanche A mass of snow, ice, and rocks falling rapidly down a mountainside
Snow Pack Layers of snow and ice built up over time
Incline The slope of a mountain
Terrain Surface features of an area of land
Slab Avalanche When the snowpack breaks away from the slope in sections
Full-Depth Avalanche Occurs when an entire snow cover, from the Earth to the surface, slides over the ground
Surface Avalanche Occurs when a layer of snow with different properties slides over another layer of snow.
Avalanche LabExamine the Board… • How would you expect “snow” to behave on each of the four surfaces? • On which surface(s) would you expect to see snow slide at a low incline? • Moderate incline? • High incline? • WHY??? • Record in your ISN!
The Snow! • Early on in the winter season, light snow will cover the area. (Sugar) • Next, winter storms dump lots of heavy snow on the mountainside. Then wind blows the snow around, breaking it into smaller crystals and depositing a dense layer. (Even Flour)
More Snow! • A long cold spell comes along. More light snow falls onto the hillside. (light layer of potato flakes) • Finally, another huge winter storm hits, followed by more wind. (even layer of flour patted down)
AVALANCHE!!! • Protractor people in place • 1 student to hold protractor • 1 student to call out angles • Eyes Peeled for Movement • Students assigned to watch each section of the board –watch for cracks and snow releases in the snowpack –collect information to record • In nature, avalanches are most common at slopes of 35 to 40 degrees!