I was going to say “earthquake” before I read 74’s post about an EMP.
Gotta agree that every other disaster would pale in comparison. Interruption of electrical service is bad enough when it’s local and counted in hours or just a few days, so I can’t imagine how utterly terrible a national or world-wide outage would be. Didn’t I read somewhere that getting replacement transformers would take a couple of years? (Quick Google search…) Yep, here’s the salient quote and the article:
If large power transformers are destroyed by a geomagnetic disturbance (GMD) electromagnetic pulse (EMP), cyber-attack, sabotage, severe weather, floods, or simply old age, parts or all of the electric grid could be down in a region for 6 months to 2 years.
http://energyskeptic.com/2015/power-transformers-that-take-up-to-2-years-to-build/
My husband has a warped sense of humor (well, so do I) and says the biggest threat after an EMP wouldn’t be no electricity but all those Millenials without their smart phones and medications.
All that being said, the overdue Cascadian Subduction Zone earthquake in my area scares me the most. We’re out of the tsunami zone in western Washington but definitely in the shake-rattle-and-roll zone of southern Puget Sound. We live earthquake prep by bolting down the house foundation and heavy objects, stuffing our old RV with preps and parking it away from the house, and planning for a life without electricity for many months after the projected 9.0 arrives — if we survive with the drop-and-cover under a table or something.