Aurora in Cuba! The Carrington Event

The strongest geomagnetic storm on record is the Carrington Event of August-September 1859, named after British astronomer Richard Carrington who witnessed the instigating solar flare with his unaided eye while he was projecting an image of the sun on a white screen. Geomagnetic activity triggered by the explosion electrified telegraph lines, shocking technicians and setting their telegraph papers on fire; Northern Lights spread as far south as Cuba and Hawaii; auroras over the Rocky Mountains were so bright, the glow woke campers who began preparing breakfast because they thought it was morning. Best estimates rank the Carrington Event as 50% or more stronger than the superstorm of May 1921.

Here's a good story from Wired:
http://www.wired.com/wiredscience/2009/09/telegraphs-ran-on-electric-air-in-crazy-magnetic-storm-150-years-ago/

I liked the bit about the telegraph operators disconnecting their batteries and continuing to work on "aurora power"!