Murky water, fast-flowing currents and large debris can only mean one thing for area rivers -- it's spring runoff.
Fish, Wildlife and Parks experts tell NBC Montana that the underwater debris is the most dangerous factor.
"Snags are a huge hazard out there, and if you don't know where one's at, or a new one pops up or a bank gets undercut and a tree falls in," Chet Crowser of Fish, Wildlife and Parks says. "There's just a lot of scenarios that can happen out there. Those are huge hazards. Strainer hazards are a big thing to be concerned about."
Strainers are any object that is not visible, which water can flow through, but a swimmer, boater or floater cannot, according to swiftwaterrescue.com.
Missoula Sheriff's Department officials say there is at least one death a year caused by hazardous waters.
Just last year a young man who jumped off the Madison Street footbridge was found dead in the Alberton Gorge.
Search and Rescue encourages folks to survey the river area before they enter, and always wear a flotation device. They also suggest that anybody intending to swim in the water should not consume alcohol before jumping in.