I would wager that many of the deaths are from homeless people that don't exactly have a closet to store their cold-weather gear in. And when snow storms hit places that normally don't get them, it's a huge deal because people don't know how to drive in it. Even if it's not artic circle cold outside
I'm not saying cold weather doesn't produce issues, especially for places unaccustomed to it. I'm saying the impact is on a different scale than from a natural disaster, so perhaps it's wise to reserve catastrophic language for potential catastrophes. If you use the same language for cold weather as you do for hurricanes, people might not take hurricanes seriously enough.
