Firefighters say the cause of Saturday afternoon's collapse is still under investigation, but there were more than 25 people on the deck at the time.
Most were taken to Kalispell Regional, but others were transported to four other hospitals.
The crowd had gathered for the memorial service of William Nickell, a Flathead Valley firefighter who died in April. KRMC Public Information Officer Allison Meilicke said patients were taken to at least five area hospitals.
Lake County Sheriff Don Bell said several police and fire crews from both Lake and Flathead Counties responded to the incident.
She walked away with bruises, but many of her friends and relatives were taken away in ambulances, she said. He says that the cause will be determined by the insurance investigator.
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Father's Day Service , 11 a.m., Change Me Ministries and Fellowship, 2310 Fort Ave., our guest speaker will be the Rev. Park Place Baptist Church , 721 Park Ave., will hear Brother Coy Sample speak on "All in the Family" at 10:45 a.m.
Other patients went to North Valley Hospital, St. Joseph Medical Center in Polson, St. Luke Community Hospital and St. Patrick Hospital. Some victims had serious injuries and had to be airlifted.
Three helicopters, including KRMC's ALERT air ambulance, were used to transport the injured.
The Somers Rural Fire Department says all patients were in stable condition as of 7 p.m. Saturday, but injuries range from mild to severe.
"When I first got on scene I saw injured people", he told NBC Montana.
The camp posted a message on its website Saturday, saying that a major accident had occurred and asked people to "please join us in praying for the injured and their families". It was established in 1931 on the western shore of Flathead Lake and, in addition to religious camps and retreats, offers wedding, event and meeting spaces.