Bigfork will host its longest-running annual event this weekend — the Bigfork Whitewater Festival.

Now in its 41st year, the competition attracts hundreds of rafters, kayakers, canoers and stand-up paddleboarders from across the country.

The festivities on the Swan River kick off Saturday at 10 a.m. with the beginner slalom, a timed race for kayaks, canoes and stand-up paddleboards held on Class 2 and 3 rapids. It begins near the power plant and finishes at the Electric Avenue bridge.

The upper slalom at 1 p.m. is an International Canoe Federation style race, with over 250 yards of continuous Class 4 rapids. It begins below the dam on the right side of the river and ends at the last gate in the Staircase rapid. Each competitor gets two runs, with the fastest counting toward his or her overall time.

Saturday also includes a stand-up paddleboarding demonstration in Bigfork Bay from noon to 4 p.m.

On Sunday, 9 a.m. is the starting time for both the triathlon and down river events. The downriver race is an all-out sprint for kayaks and canoes down the “Wild Mile,” the last one-mile section of continuous, Class 4 whitewater rapids on the Swan River.

Opening head-to-head heats for rafters begin at 11:30 a.m., followed by the giant slalom event around noon — a race with 10 to 15 gates down the Wild Mile. The final head-to-head heats for rafters start at 2:30 p.m.

The Whitewater Festival Champion is the competitor with the fastest combined time from the upper slalom, down river and giant slalom races.

A scenic nature trail parallels the Swan River’s last mile before it flows through downtown Bigfork and into Flathead Lake, giving spectators up-front views of the competition.

For more information or to register for the competition, visit www.bigforkwhitewaterfestival.com.