now. >> reporter: rick seaney is the ceo of farecompare.com. he says airlines have gotten smart and now cancel flights at the first sign of a nasty storm -- long before passengers arrive at the airport. in fact, just tonight delta announced it's letting you rebook for free if you are flying to certain cities in the northeast this week. >> how bad might this week be? >> it could be one of the worst we've seen in the last four or five years, if it really nails laguardia, jfk, philadelphia, newark, that's sort of the hub system that really causes the cascading effect to have an issue all across the country. >> reporter: the website flightaware shows that domino effect in its misery map. places like dfw and houston have lots of red for cancellations and delays. as we move into tonight and into tomorrow, atlanta, d.c. and new york it's your turn to see red. this is what the flight board looked like first thing this morning at dfw and look at it tonight, almost all the cancelleds are gone.