ELY (AP) — Forest Service officials have temporarily banned campfires in the Superior National Forest, including the Boundary Waters Canoe Area Wilderness, and closed some lakes and access points because of four wildfires burning in the area.

The Minnesota Department of Natural Resources is reporting high or very high wildfire danger across most of northern Minnesota.

The Delta fire is the largest and is burning south of Snowbank Lake about 19 miles east of Ely. Officials estimated it at 62 acres in size and believe it was caused by lightning, Minnesota Public Radio News reported.

“The Delta fire is burning in heavy blowdown, and it’s very difficult conditions for our firefighters and resources to work with,” said public information officer Christine Kolinski with the Superior National Forest. “They’re having to use chainsaws to cut out safety zones (for firefighters) to put a line around the fire and try to contain it.”

Crews are also monitoring the Astray fire about 11 miles east of Ely. It’s about an acre in size and is also believed to be caused by lightning.

The Picketts Lake fire about 4 miles northeast of Ely is less than an acre in size and is also believed to be caused by lightning.

The Hassel fire is about 10 acres in size and located west of Crab Lake about 14 miles northwest of Ely. That fire was originally reported June 4 with fire activity increasing this week.

While campfires are banned in the BWCA, they are allowed in Forest Service-installed fire structures in some developed campgrounds.