Storm & Flood Damage Recovery in Erie, PA

That is a dam of ice at the roof edge, and it is caused by heat rather than by weather. Warmth escaping into the attic melts snow on the upper roof, the meltwater runs down to an eave that is still below freezing, and it refreezes there until the water backing up behind it finds a way under the covering. Two identical houses can differ entirely on attic sealing. Clearing the eave helps for a fortnight; sealing the attic stops it.

More here than almost anywhere else in the state, and it is worth knowing what your roof was built for. Older structures were framed to expectations that have since been revised, and additions and porches are frequently the weakest parts. Clearing snow is hazardous and often unnecessary; knowing which parts of the roof accumulate and watching those is more practical than clearing the whole thing.

A winter of accumulation leaves over a couple of weeks and the ground below is still frozen hard, so none of it soaks away and all of it moves across the surface into whatever it meets. Gutters, the fall of the ground beside the house, and where the snow was piled all matter enormously in that fortnight and hardly at all in July. It is the most predictable wet event of the year here.