My question is basically that recently we have had a lot of snow, some of it is high enough to be over the damp-proof course (DPC). Should I be worried about this, or would damp penetration take longer than the snow takes to clear?
Here in Alberta this turns out to be a non-problem. What tends to happen is that the snow slides off the roof, stacks against the house. Within a day or so, heat from house melts a finger sized crevasse and the snow is no longer touching the house.
Assuming that there is reasonable siding on the house this is a non-worry item IMHO.
If however, the ground is impervious to water penetration, and you start getting a pool of water at the base of this crack, then watch that carefully that it doesn't get above the foundation course. If this happens, you need to create drainage to take care of it. I've not seen this happen in our climate.
I pile snow against the base of my house using half a sheet of plywood as a form to make a vertical wall about a foot thick. It looks like a concrete foundation but made out of snow. After a day, there is a gap about 5mm or about 3/16" between the snow and the house. This acts as extra insulation (about R1 per inch of snow) and keeps the wall that much warmer. As spring approaches, I spread the snow on the lawn away from the house where it can drain away. There is a decent temperature difference when I feel the interior wall where I have the snow and do not have the snow: especially when it gets to around -30C. Just like an igloo.