The first sign I noticed was a flicker of the lights in the local history museum I was in. A moment later they'd gone out and my pocket felt strangely hot. A dozen or so of us came to the same realization and our cell phones were soon on the ground with small lithium-fueled fires lighting up the place. A few of the women weren't so lucky - their purses were on fire along with the phones inside them.
I wish I'd been a bit more aware and had tried to put the fires out, but I panicked and rushed outside. At first I was struck by the chaos - people were rushing about and yelling all sorts of things - but after a second I noticed only people were moving. Every car was stopped, building air conditioners had ceased to hum, and every light I could see was out. A solar flare had hit and I had been in the blast zone.
Everything with a battery in it was on fire - or in danger of combustion - as the electronic pulse melted, fused, or otherwise fed back into every bit of wiring for countless miles. I'd written some software that dealt with troubleshooting and restarting broken systems after a man-made electromagnetic pulse, but it was clear this was well beyond a small malfunction in an MRI. As the population began to realize the situation, a good portion began to team up to explore the scope of the damage and rebuild. Another portion descended into senseless violence and looting. I fled.
I hope someone finds this note someday - perhaps when they reopen the quarry. Please excuse the tear marks on the paper. I don't have the skills needed to restart the world and I knew there was dynamite here. One stick. One stick and I won't have to worry about starving to death.
Goodbye and good luck.