What is "The White Spider" as noted in the nonfiction book, The White Spider: The Story of the North Face of the Eiger?

The White Spider is a field of ice in the upper reaches of the North Face of the Eiger, with icy crevices leading away from it, reminiscent of a spider's limbs. The White Spider turns into a funnel of avalanches and rock slides from above it, posing a serious danger to climbers.