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Slope Angle and Slope Aspect are available in OpenSnow to help you explore terrain features and avoid risky, steep, or avalanche-prone terrain.

Both overlays can be viewed for free on the OpenSnow website. They will be available in the iOS and Android app in future updates, along with the ability to download for offline use.

Getting Started

  1. Tap the "Maps" tab
  2. Tap the overlay button.
  3. Tap "Land Details".
  4. Select "Slope Angle" or "Slope Aspect".
  5. Tap "3D" to rotate and tilt the map.
Slope Angle

Slope Angle provides the incline of any given slope and is a critical aspect when evaluating avalanche danger in the backcountry.

Slope Angle data comes from Digital Elevation Models (DEM), which are digital representations of the height of the earth’s surface at any given location. The DEM in OpenSnow has a resolution of 30 meters for the entire globe, with the following resolution for popular ski regions:

  • United States: 1-10 meters
  • Canada: 2 meters
  • Japan: 1-10 meters
  • Austria: 1 meter
  • France: 2 meters
  • Italy: 2-10 meters
  • Norway: 1 meter
  • Switzerland: 2 meters
Slope Angle can be viewed in two ways:

  1. All Terrain
  2. Avalanche Terrain
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Slope Angle > All Terrain Legend

  • Green: slope is less than 20°
  • Yellow: 20° to 30°
  • Orange: 30° to 35°
  • Red: 35° to 45°
  • Purple: 50° to 55°
  • Blue: slope is greater than 55°
Switching into the Avalanche Terrain view via the toggle in the upper left of the map will highlight slope angles at 30° and higher, which is where most avalanches start.

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Slope Angle > Avalanche Terrain Legend

  • Orange: slope is 30° to 35°
  • Red: 35° to 45°
  • Purple: 45° to 55°
  • Blue: slope is greater than 55°
"Most slab avalanches initiate on slopes where the steepest slope angle is between 30° and 50° (about the steepness of a black diamond run at a ski hill) and subsequently run into lower angled terrain. Avalanches initiating on slopes less than 30 degrees are rare because the incline is so flat. Slopes steeper than 50 degrees are so steep that small loose avalanches run frequently so they only rarely develop the structure for larger slab avalanches." – Avalanche.org

Slope Aspect

Slope Aspect details the direction at which the terrain is facing and can be important for planning around sun exposure on the snow surface.

For example:

  • If the terrain is south-facing, it will be highlighted in red.
  • If the terrain is north-facing, it will be highlighted in blue.
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Slope Aspect Legend

  • Blue: North
  • Darker Green: Northeast
  • Lighter Green/Yellow: East
  • Orange: Southeast
  • Red: South
  • Pink: Southwest
  • Purple: West
  • Dark Blue: Northwest
  • Light Blue: North
Slope Angle and Slope Aspect are critically important for evaluating the avalanche risk, though they should never be used in isolation for assessing the current avalanche danger. Get educated with the proper avalanche safety protocols, always check the latest avalanche and weather forecast, and be responsible for your safety and others in the backcountry.

View → Slope Angle

View → Slope Aspect

Data Source: Mapterhorn