Bugge conjectured haldist or haldist r. The latter has been adopted here, although the former would essentially render the same meaning. Frost on a high mountain is surely a severe frost.
Any emendation here is totally unnecessary.
A familiar sight in the north was that of a dead body, human or animal, frozen to death, sticking out of a solid snow-drift. A terrible effect of exposure to extreme cold is frostbite, which often results in the necessary amputation of the effected limb, in order to save the victim's life.