(ABC News) -- Minnesota State Patrol pilots helped to rescue two paddlers from the Boundary Waters Canoe Area Friday morning after the pair hadn't been heard from in four days, according to a statement from authorities released on Facebook.
Pilots used a Cirrus aircraft equipped with heat-seeking technology to search near Oyster Lake on Friday, according to the Minnesota State Patrol.
The crew was able to locate a man and a woman who had not been heard from in four days, authorities said.
The two lost paddlers used flashlights and had written "SOS" in the sand to help direct the air crew's attention to their location, Minnesota State Patrol officials said.
The State Patrol then directed the Air National Guard to the location of the paddlers and they were safely rescued.
The pair had gone missing while in the Boundary Waters Canoe Area, which is located in the northeastern part of Minnesota. It is over one million acres in size and extends nearly 150 miles along the International Boundary adjacent to Canada’s Quetico Provincial Park, according to the U.S. Department of Agriculture.
The expansive BWCAW also contains over 1,200 miles of canoe routes.