A short haired dog, like a Doberman pinscher, may not do well as an avalanche or backcountry search dog because of the lack of coat and body fat necessary for warmth. On the other hand if you live in a warm clime and prefer disaster work, a smaller, short haired breed might work well for you. There are size and coat restrictions for search dogs that exist for purely practical reasons. Small breeds with short legs, like basset hounds or Pekingese don't have the stamina or agility required for search work. At the other extreme very large breeds are unable to continue working for long periods of time.
Long hair presents a problem in backcountry work.
Long, fine hair traps snow between dogs' paws, under their legs, and in other places which can prevent them from continuing their search work. Long hair also traps foxtails, ticks, and other burs more easily than short hair. For example, Afghan hounds have a coat that would be impossible to manage in the wilderness. Some handlers find even the intermediate coat of golden retrievers to be difficult to keep un-knotted. All of these are valid, important considerations when narrowing down what breed to consider.