Senior Airman Alex Ribbens, a bioenvironmental engineer from the 779th Aerospace Medicine Squadron, examines the readings of a Wet Bulb Globe Temperature Index Jan. 23, 2013 on Joint Base Andrews, Md. The monitor is used to notify the base of heat flag conditions and measurement is required of those environmental factors that most nearly correlate with deep body temperature and other physiological responses to heat. (U.S Air Force photo/Airman 1st Class Erin O’Shea)