( CNN ) -- An apparent natural gas explosion in downtown Bozeman , Montana , leveled three businesses Thursday morning , according to city and state officials . An explosion rocks downtown Bozeman , Montana , on Thursday in a photo from iReporter Sean Gallik . `` When we say gone , we mean gone . These three businesses are gone , '' said Montana Gov . Brian Schweitzer , who added that the state is providing help for clean up , and to businesses and residents who are affected . One person remained unaccounted for Thursday evening , Bozeman Assistant City Manager Chuck Winn said . `` The situation remains unsafe for anyone to enter , '' Winn said . `` So in terms of a search -- we are unable to do so at this time . '' Winn said city crews are making progress cleaning up the area , but the damage is great . He said a meeting was planned Friday morning to give business owners and residents information about when they can return . `` It literally looks like a bomb went off in downtown Bozeman , '' he said . iReport.com : Photos from the scene . `` Roofing material , construction material is scattered for three or four blocks , '' he said . `` It was a very violent explosion . '' Schweitzer added that the situation would `` not be over in 24 hours . '' The blast occurred about 8:15 a.m. on the town 's Main Street , Fire Chief Jason Shrauger told CNN . The city government declared a local emergency after the blast . Initially , 11 people were reported missing , but 10 were later accounted for , Winn said . It was not clear what triggered the blast . Bozeman is in south-central Montana , about 100 miles southeast of the state capital , Helena .
One person unaccounted for . Three businesses destroyed in downtown Bozeman , Montana . - A tornado touches down near the town of Owatonna, Oklahoma and moves through central Oklahoma destroying homes and buildings. It was not clear what triggered the blast .