Slope Angle and Avalanche Risk Window

Slope angle, slope %, and 30-45 deg avalanche start-zone flag.

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Formula and source

Slope angle (degrees) = atan(rise / run). Slope % = (rise / run) × 100. 30-45° avalanche start-zone window flagged per AIARE / USGS / Avalanche Center guidance.

AIARE (American Institute for Avalanche Research and Education) Level 1 / 2 curriculum by name; USFS National Avalanche Center materials by name.

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