Half Dome cables at 4:40 pm on June 13, 2009, right after I got off the cables. This is pretty much in the middle of the disaster unfolding, the picture was taken a few minutes before the first helicopter rescue team landed. Note that there is still a bunch of people stuck at the top of the cable unable to descend the slippery rock. I learned later that the last person got off those cables well after 8pm.
In case you are thinking of going, here is my 0.02 on the cable route:
1. In dry weather if you slip, you most likely would die. In bad weather, if you slip you definitely would die. Play it safe, bring a climbing harness and TWO carabiners on leashes, and wear it on the cables. If you see people going up in sandals and tennis shoes- don;t be embarrassed- wear your harness. It does not slow you all that much and you will be spending most of the time waiting for other people anyway. You may not get as much of adrenalin rush knowing that you are clipped in, but if you slip, you won't die, and that's definitely worth something.
2. Even if you wear a harness, chances are most other people would not, so if the weather turns bad suddenly, you will get stuck behind them, and will get hypothermia. Bring a light waterproof jacket, a light fleece vest, and an energy gel or two with you (you want something that you can eat with one hand).
3. If the weather looks anything but blue skies, DO NOT go up beyond the base of the Sub-Dome. There always will be another day to do it. Don't think that if others are going up then it is safe. People who hiked up a mile of vertical would not stop and turn around, even if it means tempting the fate. Don't do it, and play it safe. Besides, the summit view in bad weather is nothing special.