It's a common cycle, don't worry. Every year there are a few months where the sand is washed away, but it is replenished after. The rocks are there as a means of anti-errosion, to keep the road from crumbling into the water. It seems to be a bit more durastic than usual, however as Wietse said it's just the hurricanes. Number four is on it's way!!
[Edited 2004-09-24 20:55:31]
There is a fine line between a picture and a photo. The latter seems to be disappearing.