Yeah, I thought that too, Anonymous. The grass doesn't move until the cover pops up, and when it does, it gets splayed out in a direction starting from inside the manhole cover. Also, I'm not convinced it was windy enough for a Bernoulli effect.
Oh, and is this really newsworthy? Can't quite imagine this appearing on my local tv news over here unless it was a really really slow news day!
Possibly as the stormwater system is being rapidly filled and water displaces the air, air pressure builds up within sewers to a point in which it will displace those 120-lbs covers.
3 comments:
It's not Bernoulli Effect, it's just that there was air blowing up from under the cover, (trying to get out).
Yeah, I thought that too, Anonymous. The grass doesn't move until the cover pops up, and when it does, it gets splayed out in a direction starting from inside the manhole cover. Also, I'm not convinced it was windy enough for a Bernoulli effect.
Oh, and is this really newsworthy? Can't quite imagine this appearing on my local tv news over here unless it was a really really slow news day!
Possibly as the stormwater system is being rapidly filled and water displaces the air, air pressure builds up within sewers to a point in which it will displace those 120-lbs covers.
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