Homeland Security officials are warning that a major coronal mass ejection, solar flare or electromagnetic pulse may be inevitable and catastrophic to modern civilization. The devastation to the electric grid and modern infrastructure could impact the lives of more than 100 million, and cause untold casualties during prolonged outages.

Homeland Security conducted a study assessing the risks with these extreme solar events (as well as manmade EMPs).

DHS' Federal Emergency Management Agency (FEMA) stated in an internal 2012 fact sheet outlining its response plan for severe "space weather" that the actual impact and damage from a future solar storm is not known.

The report outlines the scenario for a major "coronal mass ejection" from the Sun that will first be detected by U.S. satellites. The magnetic band reaches the earth within 24 to 72 hours, affecting up to 100 million people.

The largest such storms, called G-5s, would cause transformers and transmission lines to be "severely damaged."

The storms last from hours to a day but can disrupt electric power grid operations, GPS satellites, aircraft operations, manned space flight, satellite operations, natural gas distribution pipelines, and undersea communications cables.  more at url