There are many posts that patiently explain the various reasons why more snow doesn't automatically mean no more global warming. A brief summary is found at Inhabitat:
The answer is simple: global warming causes more precipitation, which translates to more snow when temperatures dip below 32 degrees [F].
There is a clear consensus in the science community that climate change will cause more frequent and more intense storms. Storms, of all types, result from energy in the atmosphere — the more heat, the more energy. Considering that 2010 was the hottest year on record, it should be no surprise that we’ve already seen multiple mega-blizzards this season. As Al Gore explained to Bill O’Reilly, “A rise in global temperature can create all sorts of havoc, ranging from hotter dry spells to colder winters, along with increasingly violent storms, flooding, forest fires and loss of endangered species.”
In the southern hemisphere, the increased warming of the oceans during the hottest global year (that 2010 was) has caused massive flooding in Australia and Brazil as well as South Africa, as well as increased the magnitude of the hurricanes "down under". And this is what is happening concurrently with the snow storms in the northern hemisphere.
It is naive to only cast your view to the borders of the United States when trying to think about GLOBAL warming.