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Petty Officer 2nd Class Marcus Bonds checks the Wet Bulb Globe Temperature before updating the garrison home page, July 21.

Summer brings weather risks, including tornadoes, and Hurricane Hanna made landfall along the Texas coast last weekend. But, neither twisters nor tropical storms pose the greatest risk to human life, but summertime heat, according to the National Weather Service. That’s why Fort Belvoir Community Hospital’s Environmental Health Division keeps a steady eye on the sweltering temperatures.

“I monitor the Wet Bulb Globe Temperature and annotate that on the garrison home page (home.army.mil/belvoir),” said Staff Sgt. Marlon Ford, the environmental division NCOIC. “We are able to monitor heat stress levels and any environmental factors that might contribute to it.”

Unlike the official temperature reported by weather stations, which are set up in the shade, WBGT is monitored in an open, sunny space. To best calculate the amount of heat stress, several factors are combined to the apparent temperature, according to Petty Officer 2nd Class Marcus Bonds, also with Environmental Health.

“We have a machine that uses several variables to calculate WBGT: the wet bulb monitors the humidity; the dry bulb measures the temperature; the black bulb measures the radiant energy of the sun, and we use the combination of those temperatures to get the heat index and measure the categories of heat stress. This determines how long someone can work outside,” said Bonds.

“Conditions can change in a short period of time,” noted Maj. Anthony Robinson, chief of environmental health. “And, that could put people at risk, because the heat has changed, your water intake has changed; your rest and work cycle needs to change; and we have to account for all that.”

Bonds said while a weather app can report the ‘real feel’ apparent temperature, WBGT is not just the temperature, but guidance on how long people can safely work in the current temperature, taking into account the other factors.