It's kind of like tires weatherchecking and causing the casing to breakdown. The belt may not have many miles, but it is beginning to have some age. If the rubber is getting hard and breaking down-change it.
My '05 will get a new belt this summer because the rubber grooves are starting to breakdown parallel with the belt. By the way, it is not uncommon for the cracks to run across the belts.
It shouldn't be too hard to change and it will be a cheaper fix than trying to find that belt and get it put on some Sunday afternoon when you were out for a nice drive.