Multiple explosions and a fire in an underground concrete electrical vault rocked downtown Omaha and forced the evacuation of a nearby hotel, but no injuries were reported. Authorities say the incident happened Monday night when a power transformer that sits under the sidewalk next to the Doubletree Hotel caught fire. Acting Omaha Fire Battalion Chief Mickey McLaughlin says explosions from the transformer continued after firefighters arrived, producing a large amount of smoke and flames coming from the sidewalk grates over the vault. The hotel was not damaged by the nearby fire. Firefighters had the blaze under control within minutes, and hotel guests were allowed back into their rooms a short time later.