Ice dams - lived most of my life in cold, snowy states, often in old houses. One good trick is heat tapes, not cheap. Another, cheap, is a few pairs of nylon (or whatever they are now) stockings and a bag of water softener salt. Fill the stocking with salt and lay it on the roof high to low bottom slightly over the edge. Cuts a channel and lets the water flow out. Did it in a couple of houses, didn't harm the house or the plants near the house. Beats the heck out of shoveling or chopping.