Ice dam formations.
Ice dams occur where solar gain and interior building heat cause the roof snow to melt. This melt water runs down the door and eventually exits the snow, whether it’s at the bottom edge of a 3′ overhang, a 12′ overhang, or even where there’s no overhang at all. When snow is partially removed (for example, by shoveling or prompted by metal edging) the meltwater re-freezes at the new bottom edge of the snow, creating a new ice dam.
Summit Ice Melt Systems prevents icicles and ice dams from forming.
1. Here’s a covered walkway with a well developed ice dam that started at the eave, 10′ from heated area. The blanket of snow insulates the meltwater from solar gain and the heated area uphill until it re-freezes at the edge. This ice dam will continue building until it eventually reaches the heated wall line:
2. Here’s a young ice dam starting 12′ from the heated area:
3. Here’s an 8′ wide covered walkway, ice dam at edge:
4. Here’s a covered walkway where the meltwater drains under snow until it exits at the roof edge, where it begins forming ice 10′ from heated area of home:
5. Here’s an ice dam beginning to form along eave about 8′ from heated area. The heater bare cable is not doing its job:
6. Typical developing ice dams growing up the roof and over the edge into a heavy ice formation:
7. Summit Ice Melt Systems’ PRO in operation with a heated gutter to ensure safe handicap ramp access:
8. Ice dam is forming at the edge of an 8′ overhang after travelling down under a thin, but insulating, blanket of snow:
9. Ice everywhere, but note that it all starts at the bottom edge of the roof, even on the 10′ overhang:
10. Summit Ice Melt’s PRO in operation in an extreme ice dam condition. Note that adjacent unheated eave (see inset), with the same northern exposure, has developed a fearsome ice dam:
11. Fully developed ice dam. Ice started forming at the eave edge of this 3′ overhang and has grown up the roof. The ice dam ponds water from the heated area and is unable to drain-hence the name “ice dam.” Time to worry about interior leaks: 
12. Another developed ice dam, but still growing. It started along the drip edge of this 8′ overhang and had just made its way up to the heated garage area to the left: 
13. Ice forming on this gambrel roof where meltwater is exiting snow on upper roof, even re-freezing over heated living area:
14. This metal-edged eave enabled the ice and snow layer to fracture and slide off the roof. Note new ice dam forming at the fracture line. The area where this ice dam forms is extremely vulnerable to leaks as it is where the roofing panels, shingles, transition flashing, exposed fasteners, etc. all meet, and often leak. Summit’s heated standing seam metal roofing prevents this. Partial roof shoveling, a dangerous and tedious task thought by some to prevent ice dams, simply creates another new ice dam up the roof.
15. Another metal-edged eave where ice and snow was released from roof. New ice dam forms where meltwater now exits the snow, and continues all the way to the bottom of the roof. This is a very vulnerable location for an ice dam, where the busy transition of metal to shingles occurs:
16. A 12″ thick ice dam occurs at the snow fracture line along a metal-edged roof. There are lots of components in this busy transition that can leak. Eventually this block of ice will drop off the roof too, perhaps taking some roofing shingles with it and damaging whatever is below on the ground/deck/driveway/walkway: 
17. New ice dam forming at the fracture line over living area where the snow naturally shed off this steep roof: 
18. Below is the second visit for this roof snow shoveler. Despite the use of bare heat tape, an ice dam formed completely along the roof’s edge and caused leaks. The shoveler then cleared the bottom 5′ of snow off the roof. Consequently, a new ice dam re-occurred where he stopped shoveling. After new roof leaks ensued higher up the roof, it was decided to remove all the remaining snow to the ridge. The energized heat tape was completely ineffective against all of these ice formations: 
