I was there with fellow CA newbie Warlock. We were on the backside of the track and were kept completely uninformed by the track announcers. They announced rather emphatically that everyone needed to clear the pit lane immediately, but didn't let on as to the serious nature of the accident. They initially said that only 2 cars were involved, and asked that no spectators make their way to the s/f area so that track personnel could maintain easy access.
About 15 minutes later, they announced that the race would be cancelled and the rest of the schedule would be moved back. We couldn't figure out why 2 cars out of a field of 50 would necessitate cancellation, but soon found out why. One of my friends has some shots of the aftermath that I'll post if I get a chance. I'll have a bit of video, too (not of this wreck).
A bunch of fantastic old cars there, to be sure. And that V-12 Ferrari, sigh....