Today the Earth is being bathed by a solar storm caused by a Coronal Mass Ejection on the sun and later this year these are expected to increase dramatically. By the end of the year, the ISON comet is expected to make a close encounter with the sun and generate even greater solar storms.
This video is a discussion of how a solar storm, comet, or terrorist/military event may wipe out grid power to hospitals and their backup generators. The person being interviewed is the author of the popular novel “One Second After” which describes the effect of an EMP on an average community.
http://www.youtube.com/watch?v=gJlPCHynEZQ