Traveling over ice and having one character with exhaustion level 2 (speed halved) slowed the party to a dangerous level. In regular conditions, the Player’s Handbook (PHB) tells us you can travel 24 miles in a day. In difficult conditions, however, “you move at half speed in difficult terrain – moving 1 foot in difficult terrain costs 2 feet of speed – so you can cover half the normal distance in a minute, an hour, a day. (PHB p.182)” I reduced the speed furthermore because they are traveling on ice without proper equipment. The players found me rough, but I am being generous, considering.