A floating bog has blocked off the Rum River at the Soo Line Trail Trestle in Onamia, creating a dangerous situation for paddlers, the Mille Lacs County Sheriff's Office said in a Facebook post on Monday.
The bog got swept down the river and has completely blocked off the area at the trestle, the post said.
"This is a very dangerous situation" for paddlers because the blockage "has the potential to pull craft/people under the blockage and become trapped," the sheriff's office said.
People should not put their watercraft in the Rum River at the Onamia Dam and should instead launch from south of the trestle.
The Rum River, which flows 145 miles south from Mille Lacs Lake to the confluence with the Mississippi River in Anoka, is no stranger to bogs blocking the river.
The past two springs, waterways in the area of Lake Onamia and the Rum River have gotten bogged down when high water levels caused pieces of the earth to break loose and travel down the river, getting stuck on dams and trestles, according to the Mille Lacs Messenger.
In some cases, the bogs had to be removed with machinery because they were blocking the flow of water downstream and causing water levels to rise in lakes upstream.
The Rum River, which is designated by the Minnesota DNR as a wild and scenic river, is a popular spot for canoeing with Class I and Class II rapids, but the DNR notes there are several dams that must be portaged and paddlers should be alert for overhanging trees, the DNR's website says.