massive travel delays last summer. it is not in this case the airlines. instead the trouble came from a part of the system most passengers never seen. as cnn's pete muntean reports, it could cause fresh trouble again this summer. >> it was the summer of air travel meltdowns. figures from flight tracking site flight aware showed that last memorial day to labor day, airlines in the u.s. cancelled 55,000 flights and delayed a half million more. >> it was horrible. >> flight gets cancelled, then it's really tough to get on another one. >> it is frustrating. >> reporter: the blame was mostly put on the airlines, which was mostly right. >> the airlines need to be prepared to service the tickets they sell. >> reporter: now cnn has learned from internal documents that thousands of those flight delays were triggered by repeated short staffing at one federal air traffic control facility in florida. the federal aviation administration's jacksonville center facility is responsible for controlling airspace used by
as astrophycist. heavy rains knock out power for thousands, triggering massive travel delays from new england to florida. in the midwest, dangerous tornadoes barreling through the northern plains. let's bring in indra petersons, tracking all of it. what do we know, indra? >> that was a same system that brought record-breaking snowfall into the dakotas, eventually moved its way into the midwest, spawning tornadoes and then last night it made its way into the northeast, bringing hundreds of reports of damage right along with it. a powerful storm hit the east coast monday with high winds and torrential rain. in jacksonville, florida, knee deep water forced residents to use other means of transportation, some helping stranded drivers. >> got out of the jeep and started pushing.