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  • When I work at military facilities in the US, they use wet bulb globe temperature (WBGT) which adds the heating effect of direct sunlight.

    We use it to prevent heat stroke. DoD has a system of colored flags that index to the WBGT. Red and black flags indicate that folks working outside need to take breaks at some increased frequency.

    WBGT

  • I posted this elsewhere but think it's relevant here:

    For the past couple of years it’s been a lot of news of “Hottest Day Ever” to which my favorite response has always been a slightly cheeky “So far!”, but I’ve realized with the recent coverage of large swaths of the US reaching deadly wet bulb temps that that’s going to change. The headlines won’t be for the hottest day, they’ll be for the highest death count, and nobody will say the second part but we’ll all be thinking it.

  • An earlier version of this article was published in June 2021.

    I'm not sure if I should be alarmed that this is happening frequently enough to recycle older articles or comforted that we've already dealt with this trouble once before.

    • they updated it on july 4th 2023. i think when they originally wrote the article, they were explaining what wet bulb temperature meant. Now they're pointing out the frequency of reaching that threshold...which really sucks...so alarmed for sure.

    • Nothing is being dealt with, is the problem. Every year people die to heat related problems. This year there will be a lot more of them. Next year there will be a lot more than this year.

      The problem with saturated humidity is that your sweat can't evaporate to cool you. Unless you directly remove yourself from the hot and humid environment, which is sometimes possible but isn't always, any temperature above body temperature (roughly 95-98 degrees F) can and will prove fatal over long exposure. Even having moving air blow over you, like sitting in front of a fan, won't help you if it's too humid to evaporate sweat.

      Without artificial ways of cooling your environment, such as air conditioning, you're going to be pretty screwed. Many places don't have access to air conditioning at all, and the places that do have it will be using it so much that they'll constantly be doing more progressive damage to the environment, which then in turn makes the heat waves worse and snowballs it all to deal with an even worse problem next year. Repeat until mass extinction is achieved.

  • Never heard of the term "Wet bulb temperature" is this something similar to "humidex"?

    • Yes, wet bulb index takes into account the relative humidity to give a realized temperature that takes into account your body can't shed heat through sweat.

      Wet bulb temperature

    • Basically you put two old-style thermometers next to each other. One has a conventional ‘dry’ bulb. The other has damp gauze or something similar wrapped around the bulb.

      In low humidity conditions, the wet bulb thermometer will read considerably cooler as the evaporating water cools the thermometer

      At 100% humidity the two thermometers will read the same, as no water will be evaporating.

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