Crunching home through snow after a winter walk, we found ourselves on such wind-slabs, albeit more modest in scale, Swiss not Arctic. They held your weight up to a point, though you could suddenly find your foot sink into a slab, and the slabs had fissures between them like islands.
‘The front hooves, which are larger, are used in winter to break and paw through wind-slabbed snow and groundfast ice. The muskox also uses its chin for this purpose.’
Source: Barry Lopez, Arctic Dreams, 59