A six-year-old girl died Sunday afternoon after a boating accident on the Bitterroot River.

Ravalli County Sheriff Chris Hoffman said Joslyn Sage Farrell from Washington state died after the drift boat she was riding in started to sink after going over a diversion dam between Woodside and Tucker Fishing Access sites.

We're told every person in the group ended up in the river. Hoffman said Farrell and others were caught in strong currents behind the dam.

Emergency responders arrived at the scene between 2:45 and 3 p.m.

Life Flight helicopters took Farrell to St. Patrick Hospital where she was pronounced dead.

The Ravalli County Sheriff's Office and Fish Wildlife and Parks are still investigating the accident.

Farrell was spending the summer with her father in Missoula.

Officials are strongly advising boaters who float this stretch of river to portage around the dam and not attempt to float through it. The Ravalli County Sheriff's Office says the diversion dam is a hazard for boats and signs posted upriver urge caution and portage.

NBC Montana will continue to update this story as more details are available.