I'm thinking there are two possible reasons why weather could cause an issue for buried lines, especially for lines in upstate New York feeding the city: First

I'm thinking there are two possible reasons why weather could cause an issue for buried lines, especially for lines in upstate New York feeding the city: First, the cable would have to be buried deep enough where temperature fluctuations are minimal. If the temperature is allowed to fluctuate widely enough, the cable would be subject to expansion/contraction stress and could then fail. Overhead lines wouldn't have this same issue since the catenary shape of the wires allows room for this expansion and contraction -- solid earth doesn't. Secondly, if it is buried deeply enough where temperature isn't much of a factor and something fails, now you have to dig that much further to get to/repair/replace the wire. Add on top of that the dead of winter and the rural rights of way that these buried lines would likely be under and that's another big mess. Keep in mind I'm just speculating here. I'm no expert.