Wrangell Sentinel -

Heavy rains, high winds and the unique topography of the area likely caused the Nov. 20 landslide at 11-Mile.

The type of landslide that hit Wrangell is called a "debris flow" - a "notably destructive" event that is common in the region, said state geologist Barrett Salisbury at a Nov. 21 press conference. They occur when soil becomes so saturated with water that individual pieces of soil are no longer touching each other, and lack the strength to hold themselves in place.

Debris flows can reach speeds of 35 miles per hour, he said.

By studying the way water moves through the land and id...