A fire destroyed the attic level of a house in Yellow Medicine County on Sunday morning, Granite Falls Fire and Rescue said in a news release.

Firefighters from Clarkfield, Hanley Falls, Boyd, Cottonwood and Granite Falls all worked to put the fire out and help salvage parts of the home and the residents’ belongings, the Granite Falls Fire Department said.

The cause of the fire is under investigation by the Clarkfield Fire Department and the Minnesota State Fire Marshal’s Office, the news release said.

The release did not give details on the address of the house. Around 10:45 a.m. Sunday, the Granite Falls fire department was paged for mutual aid with the Clarkfield fire department to the house fire.

A volunteer firefighter who was passing by had noticed the fire, reported it, and rescued a family dog from the house, the release said. The homeowners were not at home.

The attic of the house collapsed as the fire spread, the news release said. Firefighters from five departments worked together to extinguish the blaze.

In a post on its Facebook page, the Granite Falls Fire Department said the scene was especially challenging, with hot weather and a fire that had likely been seated deeply in the home’s attic for some time.