@YurkshireLad Finally a good shot of the top floor. The snow removal folks did the wrong thing here. Instead of removing the snow load they pushed it into a corner. You can clearly see a pile still on the roof. That's a lot of weight.
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Snow piled into one spot is the cause. https://informedinfrastructure.com/92182/guidelines-to-prevent-damage-to-parking-structures-during-snow-removal/
"Do not pile snow on the deck surface. Piles of snow can exceed the rated load capacity and cause cracking in the concrete deck surface."