Be careful launching and loading in sub freezing temps. Those bunk boards get slippery.
It can get real tricky trying to load in this kind of weather too. Went out and hour or two a head of one of these monster blue northerners sevral years ago hoping to get on the bite for crappie as it blew in, big mistake. The temps dropped so much so fast by the time we made it back to the boat ramp the portion the waves were covering was froze solid. We couldn't get the truck to move with the boat on the trailer. We finally had to get the truck all the way out in the water and take a running start to get across the ice patch. Luckily this ramp was flat enough and long enough to let us get away with doing that and the boat didn't get cross ways on the trailer.