Authorities are investigating a fire that caused minor damage to a La Crosse storage building Monday afternoon. A fire was reported at 2300 South Avenue shortly after 3 p.m., according to the La Crosse Fire Department. Firefighters extinguished the fire within 10 minutes. The building, which is owned by Gundersen Health Systems and used for storage, was unoccupied at the time. It sustained minor smoke damage and damage to an exterior wall. The fire department’s Inspection Bureau is investigating the blaze.