It might be a little hard to see, but if you look close you will see that the yeast have dropped out of about the top three inches of my carboy. This is what happens when you cold crash. If I let it go long enough, it would all drop out. Unfortunately, it does not look like it is going to make it in time for me, since I need the yeast in this carboy for the beer I am making tomorrow.
Update: By the next morning, the yeast had dropped to 4½ inches. For it to drop entirely, it would have to drop 10–11 inches. Since I put it into the fridge on Wednesday evening, it has been about 56 hours since crashing. That corresponds to about a 1/12 of an inch per hour (or an inch every 12 hours). In order to drop 10 inches, it would have to crash for 5 days — 6 to be on the safe side.