High temps and near-freezing rivers made a dangerous combination as an Oregon spring heat wave set in and patrols responded to possible drowning calls Thursday.

 Also: Record temps expected

Crews in Marion County were called to the Little North Fork of the Santiam River on a presumed drowning call around 5 p.m.

River patrols checked an area of the Clackamas River near Dodge Park for two boaters reported missing Thursday afternoon. One man fell out of a raft and another jumped into save him. They declined help from rescue crews and no injuries were reported. But four of the rafters were cited for having no lifejackets.

Officials said rivers and lakes remained at only about 45 degrees.

KGW photo

The Clackamas County Sheriff's Office Marine unit patrols the river.

One problem is that anyone who jumps in the water to cool off can involuntarily gasp causing water to rush into their airways. Safety experts said one should gradually wade into cold waters.

Swimmers were advised to not go swimming alone, and supervise any children. In addition to the risks of drowning, hypothermia can set in within about ten minutes.

Add in to the cold water a fast current and high river levels, caused by rapidly melting mountain snows.

Tips: If you notice anyone in trouble in the water call 9-1-1 immediately. Do not try and rescue the person, try to throw them victim a flotation device, but don't become a victim yourself. Also take notice of the victim's clothing and try to keep other witnesses at the scene.