another example of snows ruining an Eruv:
Hilchos Shabbos 16:6 that if the Reshus Hayachid is larger than Beis Sasayim, it would ruin the Reshus if it gets full of water, making it have Din of a Karpaff.
why should snow be any more lenient than water? if snow drifts make most of the town inaccessible, it shouldn't be any better, despite the Shittos that snow doesn't count.
The question now comes up as to who must be able to access an area: pedestrians or vehicles too. In nj even vehicles were not alowed to travel the streets. so most of nj was inaccessible to both cars and walking.
some neighborhoods have more street area than home area so it is not far fetched that most of such a town's area would be innaccessible soon after a heavy snow .
B"H the snows are melting before this coming Shabbos, so no need for Kol Korah's announcing not to use an Eruv this Shabbos.
You raise a good point. However, bear in mind that just as there is an argument among the Poskim regarding how much rain would make the area unusable, so too one would have to make a Halachic calculation how this applies to snow.
All the best,
Yaakov Montrose