A ski patrol is an organization that provides emergency medical and rescue services to participants of on-snow sports such as cross-country skiing, skiing, and snowboarding, either at a ski area or in a backcountry setting. Ski patrollers provide emergency medical care with many certified through the National Ski Patrol's Outdoor Emergency Care(OEC) program. The OEC program includes all of the content found in the emergency medical service (EMS) provider level of emergency medical responder (EMR) in the United States. Many patrollers, however, may also hold credentials issued by states including emergency medical technician (EMT) or paramedic. Due to the remote location and terrain, transportation is often limited to helicopter, snowcat, snowmobile, and toboggan. Patrollers are often well versed in avalanche search and rescue and other specialized techniques (e.g., chairlift evacuation and helicopter rappelling). Patrols work to promote ski safety, enforce area policies (where applicable), and help injured skiers when necessary. Ski patrollers also work to set up the mountain before it opens by conducting trail checks, providing avalanche control work, and setting up necessary equipment in preparation for the day. At the end of the day they also conduct a sweep clearing the mountain for off-hours. Currently, the organization is made up of more than 28,000 members serving over 650 patrols.