Originally Posted by learman
I've always wandered how or if the made bump runs. Are they natural or man made? If natural what causes them, if man made what machine do they use?
A little bit of both. Most bumps you see at ski areas are natural, and they form from people turning in the same area over and over again. Snow begins to form piles, and people naturally ski around them. Then you get the fall line skiers who start skiing short-radius turns, and they form up and become what we know as "moguls."
Some ski areas "seed" mogul runs for public, and all competition courses are "seeded." There are essentially two effective methods of building a mogul run. The first and easiest is to "set" the course with marking flags (or some other easily visible object), and then ski it. Typically, the flags are set about 7 feet apart (thanks, Joe!), and patrollers or a mogul team will push snow into these flags, and moguls pop up before your eyes!
Second method is to set the course (or trail) with a snowcat. An operator will push mounds of snow where the bumps are to be located, and they are then shaped by shovel, and then skiied in.
Happy bump skiing!