"planet killing asteroid skipped across the earth's atmosphere" Well if we did get a real close shave like that I think we would be very relieved. Whether that would then cause a asteroid winter, I'm not sure, but it would definitely be scary.No it was you who said "Actually no. I'd be thinking about where to take shelter and what things I must prepare in order to survive an "asteroid winter."
To get an asteroid winter I think that implied a type of direct hit not just a skim past the Earth.
When I was looking into what one would have to do to survive an asteroid winter I came to the conclusion it would be impossible to prepare for it.
Are you preparing for the end of the world? Even if you had 1000 years to start building your shelter and food stores you wouldn't have enough time.