Are the ice dams above the areas free of spray insulation? If so, the lack of insulation caused the heat from the building to form the ice dams. Adding the insulation to areas that already have ice dams will not remove the ice dams, only melting the ice from above(warmer weather or physically melting) will remove the dams. But, once the spray insulation is installed, new ice dams should not happen.

Ice dams usually occur with incomplete insulation/venting problems. Warm air from inside the building melts the bottom layer of snow on a roof, which flows down the roof surface to a colder section which freezes at the eaves/edges of the roof. That builds up over time to cause unwanted ice buildup.

Freezing rain causes buildups of ice that looks similar, but covers everything, not just eaves/roof edges. There will be a layer of ice on the entire roof, trees, power lines, plants, everything.

Icicles form with normal thaw/freeze cycles during the day/night when the sun heat begins to melt the top layer of snow on a roof, which flows down and freezes as the water drips off the edge of the roof.

Incorrectly insulated/vented attic spaces can create a combination of ice dams and icicle buildup.

Different situations that can seem similar. The solution is to determine if the building is correctly insulated and ventilated. In your situation, freezing rain seems to have caused the problem, unless it happened on the yet to be sprayed areas.

@ JDS : We're in Montreal and we did have a few freeze-thaw cycles lately with temperatures oscillating. The roof was completely insulated, I just posted pictures during the insulation process to show the thickness of SPF.

We didn't work on the outside of the roof yet because of the snow accumulation. It was resurfaced (asphalt-gravel) 10 years ago (by the previous owner, invoice in hand) so it's supposed to last another 5. It just needs some patching here and there. However my wife and I are thinking about changing it in spring time for elastomer membrane.

@HandyMac : To my knowledge everything was sprayed, there are no missing areas. As you can see in the second picture there is a nice transition between the roof and the walls. We did have freezing rain but there's nothing on trees, power lines, etc. Thanks for pointing that out.

There were a few icicles/icedams before we did the insulation job (I took a picture of outside the house a day before where there are 3-4), but new ones appeared after that (the picture I posted is after the insulation). The coincidence is that the SPF was sprayed during a warmer day (+4C, which is exceptional in December in Montreal) and that warmer weather lasted for a week before temperatures went down to -15.

Normal with freeze thaw, if the icicles get huge then perhaps not. Only other idea is heat escaping from windows is getting in the soffit. Icicles seem more above the windows. Perhaps insulate roof inside the soffit as well.

If snow accumulates a lot you need to remove it off the roof with a roof rake. Roof can hold a fair amount of weight but a lot of snow gets pretty heavy.

@Vith, that's reassuring, thanks.

If this is a low-slope (flat) roof with built-up asphalt roofing, it should drain to an interior drain or perimeter scuppers rather than over the edge of the gravel stop. In a freeze-thaw cycle icicles would be unavoidable. I suggest contacting an experienced roofing contractor.