EMP: what to protect and how

An electromagnetic pulse is a burst of energy, from a high-altitude nuclear blast or a severe solar storm, that can overload the power grid and damage electronics. Experts expect the grid to be hit hardest. Small devices might survive or might not, and effects would be uneven.

The calm way to think about it: plan for a very long power outage, and keep a few backup electronics shielded so you know at least some will work.

• A hand-crank or battery radio so you can get news.
• Two-way radios to talk with family and neighbors.
• A spare cheap phone or old tablet loaded with offline maps, your documents, and PDF guides.
• USB flash drives with copies of IDs, insurance, medical records and photos.
• A small solar panel and power bank to recharge everything.
• LED flashlights and headlamps (keep the batteries out of them).
• Spare parts for anything you depend on, like a glucose meter or hearing aid batteries.

1. Get a galvanized steel trash can with a tight metal lid.
2. Line the inside completely with cardboard so nothing touches the metal.
3. Wrap each device in plastic or put it in a box, then put it in the can.
4. Close the lid, and run aluminum tape around the seam for a tighter seal.
5. Test it: put a radio inside tuned to a strong station, close it up. If the sound cuts out, the shielding is working. It's not a lab test, but it's a good sign.

• Some cars may stop and some may keep running. Nobody knows for sure. Keep your tank at least half full either way.
• Older vehicles with few electronics are the most likely to keep going. If you have one, keep it maintained.
• Your home's wiring and appliances could be damaged. A shielded radio and lights, plus your non-electric preps (water, food, heat, cooking), carry you through.
• Keep cash in small bills. Card readers and ATMs need power and networks.