In order to develop ski resorts, mountain areas need to be cleared of trees to develop trail systems. Runs are developed by cutting and removing trees, or by using a bulldozer to remove tree stumps and slope irregularity. This process reduces topsoil and causes soil erosion, but remains a popular method because it requires less snow pack in order to open the ski area.
Increased soil erosion increases the likelihood of landslides and bared slopes increase avalanche activity. Snow grooming machines and artificial snowmaking cause irreparable damage to soil and vegetation, as some resorts infuse their snow with salt to make the runs faster for skiers. Artificial snowmaking also uses an abundance of water and energy, further stressing resources in an area. Resort development damages local wildlife populations through destruction of habitat.
Many ski areas are developed with the permission of the Forest Service through leases of public lands. Forest Service supervision and increased awareness of protecting the environment have caused ski resorts and visitors to consider the consequences of development. Creating or expanding a ski resort is a long process, involving several preliminary stages of planning before permission to build is given and any work can commence. Developers have to work to ensure the proper environmental precautions are taken, while already developed areas work to decrease their footprint on the environment.