Yikes Pete! Talk about an avalanche.
I did the same thing Thursday on my roof ( 4 ft drifts on a tri-level ) but I keep my Webys in my garage so they are always good to go.
Any-hew, whats that blue handled thingy sticking out of your snow bank? Looks a lot like my telescoping pool pole, but was just curious if you were able to score a
roof rake before the demand went nuts.
Now regarding your ice dam, it might be an insulation issue, but IME it's usually a lack of proper soffit to ridge ventilation. But there is a catch to that, even if you had continuous ridge-soffit- vents installed, the amount of snow that you received in a short period will quickly clog your ridge vent,which is basically your exhaust to vent warm air out of your attic. So what happens is the warm air which is trapped will slowly melt the snow at the roof deck or shingle line, which causes water to run down under the snow until it hits your soffit or overhang which is cold ( and uninsulated ) and the water will quickly freeze, which causes ice dams.
And it doesn't look like you have gutters mounted on your back elevation, so I wouldn't be to worried about water working its way back up under your starter course.
Hey I hope that makes sense, cause I'm sick as a dog and between the beer and some
red stag I do kind of ramble a bit when it comes to home improvement.
HTH
Tim