Seriously though, as horrible as downtime is, I think most internet users aren't terribly surprised when they can't go to a specific website for a short period of time.
Anyone else care to speculate how this could be good press?
http://www.codinghorror.com/blog/2011/04/working-with-the-ch...
vs
"This site is so popular it barely works"
If you want to be extra paranoid, you could always pick a secondary data center location where it would be safer in the summer, since Denver would be safe from tornadoes in the winter. [2] Or you could just put one on the West Coast and hope that there's not a 1-in-a-thousand tornado within a week of a big earthquake.
[1] https://en.wikipedia.org/wiki/File:Tornado_Alley_Diagram.svg
[2] http://www.weather.com/outlook/weather-news/severe-weather/a...
Yup, everywhere has got its natural disasters.