Ski patrols are organizations that provide medical, rescue, and hazard prevention services to the injured in ski area boundaries, or sometimes beyond into backcountry settings. Many have technical-medical certifications, such as Outdoor Emergency Care (OEC) provided by the National Ski Patrol (USA), that are specific to the winter-season environment and providing emergency medical services in remote locations. Many patrollers also hold EMS issued credentials, such as Emergency Medical Technician (EMT) or any other pre-hospital care certification. Due to the remote location and terrain, transportation is often limited to ski toboggan, snowmobile, or, for life-compromising injuries or extremely remote terrain, helicopter rescue. Depending on the ski area terrain, ski patrollers can be versed in a large variety of specialized rescues, such as avalanche search and rescue, Outdoor Emergency Transportation, chairlift evacuation, and, in some cases, helicopter rescue techniques are taught. Patrols work to promote ski safety, enforce area policies (where applicable), and help the injured within their jurisdiction. 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 29,000 members serving over 650 patrols.