The Valhalla Wilderness Society, who apparently did a lot of the campaigning to protect this area, does use the term "rock and ice", but it refers to a much smaller area than you describe. Taken from their press release (https://www.vws.org/incomappleux/)
“At 58,000 hectares, the promised new Incomappleux Conservancy is relatively large,” says Pettitt. “VWS is pleased that it takes in the entirety of the Incomappleux unit of our park proposal. The Conservancy is close to twice as large as the Incomappleux unit of VWS’s park proposal; but the extra is mostly clearcuts, inoperable terrain, rock and ice."
So a little under half of the conservancy is "clearcuts, inoperable terrain, rock and ice." That's very different from 94% being "rock and ice" [(58,000-3,600)/58,000 ha].