WSPR - Low Power Beacons and Beaconing (and snow...)

I'm not sure if the word "Beaconing" actually exists or if I've just made it up. WSPR has been around for a while and as I am enjoying a break from work, and am "excused" household DiY duties on the basis that (a) it's Christmas and (b) it's freezing cold, I have been up to some serious dabbling with my Amateur Radio hobby. My objective this holiday was to get stuck into Eden Valley Radio Society's "Eden 9 Project" - a 70MHz SSB QRP transceiver, and at the moment I haven't made much forward progress, but I still intend to do so. However, WSPR crept into my consciousness again and I indulged myself, and as often happens with these kind of specialist interests, things spiralled off in a slightly different direction to that which I intended. To cut a long story short the unusually cold weather has deposited quite a significant amount of snow on the roof of my house, and the roof of my house is where some of my Amateur Radio antennae are. It is trying to analyse (albeit in a casual, qualitative way) the effect of that snow on the performance of my WSPR set-up which has taken me off in flights of fantasy and let me to the conclusion that the "double helping" of snow has reduced the potency of my WSPR transmissions by around 13 dB, or to one twentieth of what it was before, in layman's terms. Well that is something I didn't know a couple of days ago! In case you don't know what either snow looks like, or indeed a roof, then may I refer you to Snow