Undercut rock hazard is defined as which of the following?

• A. Water flows beneath rock ledge
• B. Tidal race
• C. Overfall
• D. Undercut rock hazard

Answer: (D)

Undercut rock hazard refers to a rock ledge where erosion has hollowed out the base, creating an overhang and a void beneath. This situation is hazardous because the overhanging rock can break away, potentially striking a kayak or a paddler, especially when waves or current affect the area. The other descriptions describe related phenomena but not the hazard by name: water flowing beneath a rock ledge explains how the undercut forms but isn’t the hazard’s label; a tidal race is fast, turbulent water from tidal flow; and an overfall is water dropping over a ledge, which is a different feature. So, naming the hazard itself as undercut rock hazard captures the specific risk described by this feature.