Though disasters like the 11-Mile landslide are infrequent, they’re not unprecedented in Wrangell. In October 1979, a hillside at 1.4-Mile Zimovia Highway gave way, covering more than 20 acres with mud, trees and debris.
The town had almost nine inches of rain in the first nine days of the month that year, including a record 24-hour rainfall of 4.49 inches on Oct. 9, the day of the slide.
No one was seriously injured and the mudslide did not directly hit any residences. It followed the route of an apartment building driveway as it crossed Zimovia Highway, picking up and dumping a car on the beachfront.
Reporting in the Wrangell Sentinel said more than a dozen residences were evacuated for a couple of days until state, federal and local officials inspected the mountainside and decided that people could return to their homes, apartments and trailers.
The heavy rains cascading down the slope helped to cover the city cemetery in about a foot of water.
U.S. Forest Service officials reported there were three separate slides on the steep slope, which reached a 60-degree incline at its most vertical points.
The longest of the slides ran about 1,000 feet, starting at the 1,200-foot level on the 2,750-foot mountain, according to the Forest Service. The mud and fallen trees covered about 15 acres on the hillside and more than five acres as it flattened out at the bottom.
A Forest Service official said damage to the slope from a November 1978 severe windstorm, which blew down countless trees, “aggravated the failure potential” on the slope.
“The problem was the heavy rain and the very thin soil cover on the bedrock,” a state geologist said.
A Forest Service inspection of the mountainside found that the area had been hit by two or three smaller slides in the early 1970s.
Reader Comments(0)