Montana Fish, Wildlife and Parks issued a warning Tuesday afternoon after a Billings man drowned while floating the Smith River and a man and woman were swept down Belt Creek.
Neither the man nor the couple was wearing a life jacket.
Officials said a middle-aged Billings man drowned Monday while floating the Smith River about eight miles upstream of the Eden Bridge take-out, south of Great Falls.
He was with another man when their boat hit a rock broadside, swamped and threw both men into the river. The victim became pinned on a rock midstream, witnesses at the scene said.
He was not wearing a life jacket, a witness said.
At Eden Bridge, the Smith was flowing almost 1,700 cubic feet per second at the time of the accident. The long-term average is about 950 cfs.
Water temperature was in the low 50s.
FWP officials said a person without a life jacket can drown in a matter of minutes when falling into cold water.
Everyone in a boat or even near rapidly flowing water should wear a well-fitted life jacket.
On Sunday, a man and a woman wading in Belt Creek east of Great Falls were swept downstream in a remote section of Sluice Boxes State Park.
Neither person wore a life jacket, but that story had a better ending, as both individuals were able to scramble up a cliff face and escape the canyon.
The man reportedly said he surprised at the strength of the water, even though he is a good swimmer.
FWP reported that rivers throughout Montana are running high from melting snow and rain this year.