On Thursday morning, April 13, 2006, the northeast turret of Miners Castle collapsed. One turret remains on Miners Castle, the best-known feature of Pictured Rocks National Lakeshore. The collapse was reported via cell phone by fisherman in the area, according to chief ranger Larry Hach.
Most of the rock fell north and into Lake Superior, and there were no injuries. The lower overlook platform near Miners Castle appears to be unaffected.
While the rockfall at Miners Castle on April 13 was startling, such events are not rare along the Pictured Rocks escarpment. At least five major falls have occurred over the past dozen years: 1) two different portions of Grand Portal Point, 2) the eastern side of Indian Head just east of Grand Portal Point, 3) Miners Falls just below the (now modified) viewing platform, and 4) beneath the lip of Munising Falls (along the former trail that went behind the cascade).
All the rockfalls involved the same rock unit, the Miners Castle Member of the Munising Formation. Rock units are named for places where they were first technically described. The Miners Castle Member consists of crumbly cross-bedded sandstone that is poorly cemented by secondary quartz, according to U.S. Geological Survey Research Ecologist Walter Loope.
Rockfalls along the cliffs typically occur in the spring and fall due to freezing and thawing action of Mother Nature.
For more information...
Geologic Formations
Weather and Climate
Climate Change
Source: U.S. Department of the Interior, National Park Service
