This was actually a "minor" event in terms of interference with our critical infrastructure. The worst case event would do much more damage.
At the Center for Regional Disaster Resilience (CRDR) we hosted, via a partnership with King County's Office of Emergency Management (OEM), a workshop: "Interdependencies Workshop:Long-term Power Outage."
Check out the link above since there are some good references listed there if you want to read up on this particular hazard that "is lurking" out there in our future.
Steve Myers shared the link to the story on the most recent geomagnetic storm.