The Maryland Natural Resources Police has issued a warning to boaters and anglers to avoid the Upper Potomac River, including its swollen creeks and streams through Monday.

The advisory, issued Friday and based on information received from the National Weather Service and the Maryland Emergency Management Agency, covers the river from Cumberland to Great Falls. It will be extended Monday afternoon, if necessary.

The water levels pose a threat to non white-water vessels, tubers, anglers and other recreational users and are caused by wave action, water velocity and treacherous currents. The warning does not apply to professionally guided river trips.

For the latest information on Potomac River conditions between Cumberland and Little Falls, call the National Weather Service at 703-996-2200.

The NRP also issued a navigational warning for paddlers to beware of two major logjams on the Monocacy River in Frederick County, one of which almost claimed the life of a kayaker.

The obstructions are at the Gas House Pike Bridge and a CSX railroad bridge. NRP officers on patrol will warn people of the dangers as state officials assess the sites to determine how best to alleviate the problem. Paddlers are urged to travel out and around the obstructions.

National Safe Boating Week runs through Friday. The National Safe Boating Council's "Wear It!" campaign promoting safe boating and life jacket wear will continue throughout the summer.

U.S. Coast Guard statistics show that drowning was the reported cause of death in almost three-fourths of recreational boating fatalities, and that 85 percent of those who drowned were not wearing life jackets. Maryland had the sixth-most boating accidents in the nation in 2012 with 145.

For more information, go to safeboatingcampaign.com.