Yup, I now about those cases. We live in MA.

In fact the guy installing our new system talked about this.
Apparently the vents were installed too low to the ground. Ours will
be about five feet above grade which should be fine. The snow is not
plowed against that side of the house. Also there are lots of high
bushes protecting that side. Drifting snow tends to get stopped by the
bushes. In addition there is a new law that requires a carbon monoxide
alarm in the furnace room. We also have one on each floor.

We were more worried about the water issue. As it turns out we
misunderstood. The condensation gets pumped out of our existing drain.
Yes, if the pump goes there can be a problem. Same thing with the air
conditioner. We had that happen to our central air. We had water but
not a flood. A flood is when your hot water heater leaks for a month
while you're in Florida. Now that was a REAL nightmare.