A Bismarck Fire Department crew driving by the Kelly Inn on Thursday night noticed smoke and fire on the rooftop, prompting the evacuation of the hotel.

The crew discovered a rooftop heating unit on fire about 10:10 p.m. at the hotel at 1800 N. 12th St., according to Bismarck Fire Marshal Owen Fitzsimmons.

No injuries were reported. About 30 people who were staying at the Kelly Inn were relocated to other area hotels, said Kelly Inn general manager Diane Rieger.

Fire crews accessed the roof to extinguish the fire and remove burned and smoldering materials, maintaining watch over the building overnight.

The crew members who noticed the fire were returning from a medical call when they drove by the Kelly Inn.

“It just happened to be the chance that that fire crew was passing by at the time and noticed the fire,” Fitzsimmons said Friday morning. “It allowed for a quick reaction, a quick response.”

The cause of the fire has been ruled accidental.

The fire caused smoke damage, but no structural damage, Rieger said. The hotel plans to reopen to customers on Sunday, she said.

Rieger said she was grateful for the quick response from firefighters and the Bismarck Police Department, which assisted with the evacuation.

“They were phenomenal,” Rieger said.

(Reach Amy Dalrymple at 701-250-8267 or Amy.Dalrymple@bismarcktribune.com)