When something major happens in our lives, we remember the strangest details. The smell of the car, the music on the radio, what we ate. One of the biggest things that people remember about that day thirteen years ago was the sky. Damn, that was a blue sky.

Much like those "where were you" conversation starters, the weather is the ultimate conversation piece and a powerful uniting factor. Everyone experiences the weather, and not a retrospective goes by without multiple people mentioning one thing: the weather was simply gorgeous that day. I grew up near Washington D.C. in northern Virginia and I remember staring at the vivid blue sky that morning. Every video of that day shows the dichotomy between the horror below and the crystal clear sky above.

Pilots and meteorologists like to refer to a deep, brilliantly-blue sky as "severe clear." An atmosphere dominated by a strong high pressure often features nothing but vivid blue, bright sunshine, and a light wind. The weather usually plays a huge role in our lives when it turns sour. A tornado. A hurricane. A flood. But who remembers such a pristine atmosphere for more than a few days? The weather that morning was perfect thanks to a cold front that had swung through just a few hours earlier. If the front and its associated rain/clouds came through any later, there's a chance that it may have quite literally changed the course world history.

Whenever we have a particularly bad thunderstorm, I remember the intense wind and hail that fell the evening after my grandmother's funeral. Every time I walk outside on a cold winter's night and detect the faint smell of a wood fireplace, it immediately puts me back in high school when I would walk down the middle of my empty street at midnight, the fresh snow crunching beneath my feet.

Small things can be a powerful trigger, and big things etch into our brains the smallest details. History is filled with days where we humans remember terrible weather events, but there is not another time in history where the lack of weather was so noteworthy.

[top image by the author, map via NOAA]

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