Two anglers fished off of Green's Point on the Mississippi River Monday, Sept 27, 2010 near Brainerd, MN. With the changing fall leaf color, the river corridor is prime place to view the changing autumn color. (AP Photo/Brainerd Dispatch, Steve Kohls) (Steve Kohls)

Anglers, duck hunters and canoeists should use caution if they're navigating rivers and streams in southern Minnesota, the Minnesota Department of Natural Resources is warning.

The Mississippi, Minnesota and lower St. Croix Rivers are flooding, and swift currents and submerged debris pose dangers to boaters on the water, DNR officials say.

Tim Smalley, DNR water safety specialist, said boaters might not see debris that is floating just under the surface of the water. He said water currents are dangerously swift, and may be difficult to swim, even for experienced swimmers, if a boat or canoe were to capsize.

DNR officials anticipate more boaters on the water this weekend with the duck season opening Saturday and fall leaf colors reaching their peak.

Fort Snelling State Park has been closed until further notice. Some trails and campgrounds have been closed at seven other state parks.

River levels are updated weekly at the DNR's website at www.mndnr.gov/river—levels/index.html.

Trail closures and campground conditions are at www.dnr.state.mn.us/trailconditions/index.html.