FORT SMITH, Ark. -- Fort Smith Fire Chief Richardson said early Thursday morning crews realized they would not be able to stop the fire engulfing the old Fort Chaffee hospital complex and they knew the fire would move westward. Richardson said they are doing what they call a "burn back." This means they started a fire on the edge of property they want to protect. They will let this fire burn and then put it out. They hope once the original fire meets the burned land it will have nowhere else to go.