vent pipe damage/leak

I have a four year old home with metal gambrel roof. For the first time, I have damage to the vent pipe seal creating leakage around the vent pipe. This single vent pipe is the only protrusion through the roof. It was a prolonged cold winter with above average snowfall and there was no melting. As a result the roof did not clear after snowfalls as had been the case in previous years. As a result, there was a two foot build up. I suspect the weight of this compacted snow and ice pushed against the vent pipe enough to break the seal. There is no damage to the pipe itself. I have seen ads for a vent pipe guard (Snojax.com) but haven't found anyone familiar with its use. Is this something that should have been installed as part of the roof? I'm reluctant to but four lag bolts through the steel roof to install the vent guard product, unless I'm convinced the vent guard is worth the cost and will prevent this damage in the future. I'd appreciate any feedback and experience with this or similar product.