First off, sorry for your loss. That sucks.
Second, the pipe is a dimple/lattice carved pipe, there are thinner area's on the pipe that are more susceptible to flaws and cracks.
Third, because the pipe is more susceptible to those flaws/cracks, temperature changes can impact those flaws/cracks causing the pipe to break like it did. Those can be caused by smoking the pipe too hot for an extended period of time or significant temperature changes in the air.
Fourth, temperature changes need to be substantial. Going from a warm room to a cold room won't do it. Going from room temp to below freezing temps and smoking the pipe can definitely make an impact. I've smoked my meers in 40/50 degree temps and haven't had an issue.
Fifth, my guess is the pipe already had a flaw/crack that had gone unnoticed, and when you stepped out of your warm truck into the cold air, the stress from the hot to cold was too much and the pipe broke. It happens unfortunately.
Good luck with the new meer. May it bring you many happy smokes.