I always knew to avoid water drains because our skinny tires could get stuck, but those are only for water drains big and long enough to get stuck in. I usually go over ones that have tiny holes that can't do any damage.
Riding down market street in SF I knew there were some huge water drains (are they even drains? they're huge, anyways...). I biked over a few water drains which were fine for my tires since the holes were tiny and they ran perpendicular to my tires, not parallel.
So i overgeneralized and headed towards another drain only to see that these holes were much larger and they ran parallel to my tires. They weren't huge so i didn't get stuck but they were big enough to cause pinch flats.. flatSSSSS.
I tried going diagonal over them and lifting the weight off my front/rear tires but it was already too late.
Anything similar happen to anybody else before?