BEMIDJI, Minn. (WCCO/AP) — Boy Scout leader says 2 campers have died in severe thunderstorms in northern Minnesota.

Emergency responders worked to evacuate several injured campers from the Superior National Forest in northeastern Minnesota where a strong storm knocked down trees and caused other damage.

St. Louis County Sheriff’s Lt. Nate Skelton says two or three campers suffered injuries in the storm early Thursday, including one who was taken from the Boundary Waters Canoe Area Wilderness by seaplane. A medical helicopter was staging at Moose Lake to transport another injured camper.

Skelton says the injured people are among nine campers at Basswood Lake who will be evacuated as crews work to clear trees in order to reach them.

WCCO’s Bill Hudson confirmed from the U.S. Forestry Service that there are at least two people confirmed dead from the storms. The Forestry Service also says portages are blocked and they are responding to rescue efforts.

The storm which packed destructive winds knocked down trees and power lines elsewhere in Minnesota, leaving tens of thousands of people without service from Duluth to the Twin Cities on what could be the hottest day of the year.