Thanks! I feel for you, it's cold here too but not nearly as cold as you have it I presume. The posted picture was in 2 degrees C. Hope the snow melts for you soon!
They actually are a throw over attachment, attached to each other with two velcro straps and each bag attached with two straps to the bike. I usually fill them with clothes and other lightweight stuff, so they probably look heavier than they are.
Nice bike, love the colour!