Ice build up on the roof overhang
This is typical of ice - damming: the gutters fill with ice, which backs up behind the gutters and creates icicles.
Ice coming out the soffit
Have you ever seen ice coming from what should be the inside of the house? This occurs once the ice build up on the roof is severe enough to push water back upwards, under the shingles, where it finds its way into the roof structure and eventually out the overhang. Just think what happens when that same water finds its way into the top of your walls...or even across your ceiling!
Ice in the roof valley
Roof valleys are often the worst areas for developing ice...and then ice-damming. Why? Well the roof valley funnels all the melt-off water (melted from the heat you paid to put into your house) on your roof into a small area. When all this water hits the cold roof overhang, it freezes, backs up, and can cause serious damage as it pushes up your roofing shingles and eventually finds its way into your house.
Snow melting of roof, causing ice build up
This is a great visual example of the heat from within the house melting the roof snow, which in turn is building up at the roof edge as ice and icicles. You can even see the roof rafters in this melting pattern!