WBGTI

This is getting to be a pretty important acronym for me out here. The Wet-Bulb-Globe-Temperature Index, the Navy and Marine Corps’ preferred heat index, incorporates the temperature at which evaporation is occurring in the atmosphere. The Marine Corps communicates the heat index to it’s personnel via a colored flag that is flown in various locations on base, including in front of the Group Aid Station (GAS): White Flag (WBGTI less than 80): No current restrictions; Green Flag (WBGTI of 80 to 84.9 degrees F): Heavy exercises, for unacclimatized personnel, should be conducted with caution and under constant supervision; Yellow Flag (WBGTI of 85 to 87.9 degrees F): Strenuous exercises or physical labor should be curtailed for unacclimatized, newly assigned Marines and Civilian Marines in their first 3 weeks. Avoid outdoor classes or work in the sun; Red Flag (WBGTI of 88 to 89 degrees F): All PT or very strenuous work should be curtailed for those not thoroughly acclimatized by at least 3 weeks. Personnel not thoroughly acclimatized may carry on limited activity not to exceed 6 hours per day; Black Flag (WBGTI of 90 and above degrees F): All nonessential physical activity should be halted.

The WBGTI makes a big difference, and temperature is (apparently) one of the least important factors. For instance, the next four days here will be 1. 99F, 2. 94F, 3. 99F, and 4. 95F. However, for each of those days, the flag condition will be 1. red, 2. black, 3. yellow, 4. green. However, these guys who came up with the WBGTI were right on the money, and I’ve learned to adhere to the flag conditions.

Semper Fi, Jon G.