Stop in for a cup of coffee

We had to travel in a blizzard to catch a flight. Only vehicle on the road at 04:00. Pounding through drifts high as bumper on the caravan. Ten miles from home,battery light comes on.
We stop and open hood, to find engine bay packed full of snow.
Just a black strip where the belt was running. We kept going, 50 more miles and it never quit.
Guess alternator slowed down enough to set off a warning.