Considering the unpredictable nature of natural catastrophes and accidents, it is always best to remain prepared by backing up all data offsite.
Some disasters do not merely lead to temporary system downtime; they can wreck the entire system. Examples are natural hazards. Whatever is harmful to property (and people) is harmful to computers and communications systems. This certainly includes natural disasters: fires, floods, earthquakes, tornadoes, hurricanes, blizzards, and the like. If they inflict damage over a wide area, as have ice storms in eastern Canada, hurricanes
in the Gulf Coast states (for example, Katrina in 2005) , and earthquakes
in New Zealand (2010) and Japan (2010, 2011), tsunamis (such as in Thailand in 2004 and Japan in 2011), and frequent fires in southwestern U.S. states (such as Texas), natural hazards can disable all the electronic systems we take for granted. Without power and communications connections, not just computers but cellphones, automated teller machines, credit card verifiers, and bank computers are useless.