River Incident Report #830283
Date of Incident: August 17, 1983
Section of River: Cataract Canyon
Location on River: Mile 208.4
Relative Flow: N/A
Gage Reading: N/A
Type of Incident: Collapsed Silt Bank
Injuries: Fractured Spine
Type of Trip: Commercial
Type of Boat: N/A
A 50 year old woman was sitting by the river at the base of a cut bank at Rapid 10 when the bank collapsed on her. The woman was in pain and could move neither her arms nor her legs. The incident was reported to Park Rangers camped at Rapid 1 by the woman's son at 16:30. A medical helicopter was summoned and the woman was evacuated at 20:50. Officials at the hospital stated the woman had suffered a compression fracture of the spine.
The depth of silt and sand deposited by a falling river can be many feet, and when the river rises again, the deposits, being slightly indurated, may be eroded in vertical faces more than 10 feet high. A considerable weight is involved when tall faces founder, which commonly occurs in the spring when rising water in the river saturates and weakens the base of the deposits. Although unusual in August, the banks may give way at anytime and perhaps from other causes. It is never safe to be immediately below them.