Light snow fell Sunday afternoon on the southeast side of Mt. Washington as Boston entrepreneur Norman Priebatsch and his son Seth hiked icy Tuckerman’s Ravine, a raw alpine ski mecca in New Hampshire. Mr. Priebatsch who had skiied the ravine many times, declared the sport too dangerous that day with the early thaw. Instead, he led Seth and two friends on a hike. Gazing out over the White Mountains, they asked him what was the most spectacular place he had ever seen on his worldwide travels. “We’re right there now,’’ Mr. Priebatsch replied. Minutes later, Mr. Priebatsch slipped and fell at least 100 feet into a crevasse. Rescuers could descend only 50 feet before the opening narrowed and conditions became too unsafe to continue the search.