A fire inside a heating and air conditioning vent was discovered Thursday morning at the Turlock Walmart and prompted an evacuation of the store. Around 8 a.m. Thursday the Turlock Fire Department was dispatched to the Walmart at 2111 Fulkerth Rd. for a report of a potential structure fire at the store. The first firefighters to arrive at the scene found light smoke coming from HVAC vents inside the store.