Firefighters from the City of Altus practice a technique called hydraulic ventilation to cool down and clear the smoke out of the room during structural live fire training, June 24, 2015. Hydraulic ventilation is when smoke and heat are forced out of a room through a door or window using a wide spray of water from a fire hose. (U.S. Air Force photo by Airman 1st Class Megan E. Acs/Released)