A cross with enough hydro could definitely melt the line if the voltage is high enough or Comcast failed to protect the line to a source of ground. As stated above me, I would suggest Comcast needs to come back out. Are they suggesting the cross is your your home? If its in their Plant they would still be unable to work on it, but should be giving you some indication on a ETA to have it fixed. And they should be referring it to the Network Maintenance group, who may have to get the local hydro provider involved.
