You begin to climb the stairs. Taking your time, there's no real danger from the ice-any slight missteps are easy enough to be mitigated by your companions.

As you go, you see something moving underneath the thick layer of snow and ice a bit above you, where the terrain has leveled out a little bit. Whatever it is, it's at least the size of a horse, and is making its way towards your general direction. It is currently some 100' away.