Quote Originally Posted by li10up
The tire was less than a year old and only had about 1000 miles on it. I did have a nick in the tire (not the tube) that I had patched about 6 months ago but it was in a totally different spot, not even near where this one occured. It used to cause me to get slow leaks overnight. But after I patched the tire I didn't get any more flats. So I don't guess the LBS would replace it.

Could riding on a very rough road cause this? I HATE CHIP AND SEAL ROADS!!
Bad roads shouldn't generally cause this. A tire should have enough tread and enough resilience to handle rough roads. Unless a substantial fraction of the tread is already worn off. Or the tire has aged and lost resilience. Impacts on rough roads are more likely to damage your rims than your tires, unless the tires are underpressured. Possibly a specific impact on a bad pothole or rock damaged some of the threads in that area and they eventually weakened to the breaking point.