Tongass National Forest

The map below shows the vicinity of the North Thorne watershed, one of the many watersheds on Prince of Wales Island.

You may click on either map to enlarge.

Soils are the medium between bedrock and vegetation. They play an important role in the watershed by acting as a sponge to store water, and as a filter to clean it. Soils can be used to interpret the past and lend valulable information to future management planning.

Mass Movement Index (MMI) is a tool we use to identify areas where soils may be unstable and prone to landslide. The map identifies the mass movement potential in the North Thorne Project area.

• MM1 (blue) is low hazard areas
• MM4 (red) is high hazard areas