The landslide that blocked the Park Road in Denali National Park late last month has been mostly cleared. Now, Park staff are trying to determine when and how the landslide occurred.
An update on the Park’s website says that ground, aerial, and satellite imagery are being studied from the months and years before the slide to see if there are any clues. The National Park Service says that it looks like a small landslide had occurred in the same area, near Mile 37 of the Park Road, in the past. While the cause is uncertain, Park staff speculate that repeated freezing and thawing or the sliding of permafrost on unfrozen clay may have sparked the 600 foot long landslide.
Park staff are also trying to determine exactly when the slide occurred. It was discovered on October 23rd. Denali National Park is partnering with the Alaska Earthquake Information Center to see if the landslide registered on seismographs. Eyewitness accounts of conditions in the area are also being sought. According the Park, the last confirmed visitors in the area were on October 12th. They are asking that anyone who was near the landslide site between those dates contact the Park’s geologist.