Only saw part of the clip, but I would gues a rear wheel made contact with a front wheel? Car in front's back end is forced down, car behind ..front is forced up. airflow goes under car and ........"Come fly with me, let's fly...etc"
Accordning to an article in Racecar Engineerng the Indy people are looking at a complete car re-design to stop this happening.
Indycar 2012: Swift | Teams | Racecar Engineering
Bet that gets a bit more attention now!