More than 40 people gathered on the deck during a birthday party to take a photo when the wooden deck caved in
Deck Collapse at Zoi's Restaurant
Credit: HamCoTNES/Twitter

Eleven people were injured on Saturday afternoon after a restaurant deck collapsed in Soddy-Daisy, Tennessee.

More than 40 people gathered to celebrate a birthday party at the waterfront eatery Zois Harbor Lights Restaurant, overlooking Chickamauga Lake. The group huddled together on the wooden deck for a photo before it caved in under their weight and splintered.

Sondra Teligades, one of the people injured, told WTVC that she heard a crackling noise before she fell about two stories. Teligades was treated for a concussion and rib contusions, and she's now back at home.

Five ambulances and firefighters from Dallas Bay and Soddy-Daisy responded to a 911 call at around 4 p.m. local time.

Emergency responders worked together for about an hour and 15 minutes to extricate people from under the deck and administer first aid at the scene, Amy E. Maxwell of the Hamilton County Office of Emergency Management tells PEOPLE.

Deck Collapse at Zoi's Restaurant
Credit: HamCoTNES/Twitter

The 11 injured people were transported to a local hospital via ambulance, and two of those people sustained critical injuries.

The cause of the collapse is currently unknown.

Hamilton County Building Codes Department has been notified, and they will inspect the deck to determine the cause.