An Army Corps of Engineers volunteer was seriously injured in an incident at Lake Red Rock Thursday afternoon.

Marion County Sheriff Jason Sandholdt tells KNIA/KRLS News his office received a call at 1:37 p.m. that a tree trunk had fallen on a woman while a group of volunteers were cleaning trails near South Tailwater. He says that 60-year-old Alta Gajdan was transported by Mercy Two Helicopter to a Des Moines hospital.

The Marion County Sheriff’s Office, Iowa State Patrol, the Army Corps of Engineers, and Knoxville Fire and Rescue all responded.