I know there are going to be a number of posts/threads about George's recent mishap, but for what it's worth I don't think it could have been the result of a broken steerer tube. According to cyclingnews.com he was riding a special Bontrager aluminium steerer tube sprayed black. I think it's unlikely that an aluminium steerer tube would have failed in such a fashion.
It looked like either a broken stem or the stem simply slipping off the top of the steerer tube. It's not like he was pulling hard on the bars when the failure occurred, which leads me to believe that it could have been slippage. I'm probably wrong and we'll know in the morning what happened, but looking at it closely on slowmo, it looks like an innocuous bit of slippage. A bit bizarre all the same, no?
It looked like either a broken stem or the stem simply slipping off the top of the steerer tube. It's not like he was pulling hard on the bars when the failure occurred, which leads me to believe that it could have been slippage. I'm probably wrong and we'll know in the morning what happened, but looking at it closely on slowmo, it looks like an innocuous bit of slippage. A bit bizarre all the same, no?