Amateur weather forecasting is one of my hobbies. From the pics I've seen of the event, I'd be unbelievably surprised if what was seen was anything other than contrails (for those of you unfamiliar with the term, they're formed from airplane exhaust). For me, this isn't anything to be concerned about. It's like people seeing a low cloud rising from behind trees during a thunderstorm and automatically thinking they're looking at a tornado; there's a bit of freak-out at first because the worst is assumed, but once the evidence is examined, it's obvious nothing harmful was going on. (Here are some fake-nados for those of you interested in weather: http://www.stormeyes.org/tornado/faq/notahose.htm)