Sharon Packer is a cheerful woman who has thought of every dismal possibility. For example: a massive earthquake along the Wasatch Front in the dead of winter, a nuclear bomb that explodes when you're driving on the freeway, an electromagnetic pulse that wipes out America's entire electrical grid.

These are not idle musings. Packer is executive director of The American Civil Defense Association, whose headquarters were relocated to Utah from Florida last summer. To sit down with her for a couple of hours is to be forced not only to acknowledge that no, you yourself don't yet have a 72-hour kit, but also to think about the most unthinkable catastrophes and their grim ramifications — for which even a 72-hour kit won't be enough.

Some people are risk-averse and some people are risk-takers, but Packer is something else: risk-confident.

On an impossibly beautiful winter day, with the sun glinting off the snow in the pastures outside her house in Wasatch County, she explains her philosophy. "Deep inside, I do think something bad is going to happen." Then she explains herself: "I consider myself an optimist." Then she laughs, and adds: "I'm optimistic that something bad is going to happen — and that I can survive it."

No hope of survival?

Most Americans, on the other hand, either don't think about risks or don't think they can live through them. This is what Packer hears all the time: "If there's a nuclear war, I'd rather just die right away." What these people don't understand, she says, is that nuclear war is survivable. So is electromagnetic pulse damage, which she predicts could kill half of the U.S. population — 150 million unprepared people — within the first six months of an attack.

You don't think any of this is going to happen? That's not the point. Packer is all about could.

Let's say she's driving down Parleys Canyon and all of a sudden the radio station she's listening to goes off the air and her car stalls and she looks around and all the other cars on the road are stopped too. Packer has pictured this scenario many times.

This will be a signal that the country has been the victim of an electromagnetic pulse attack. EMP — the intense electrical pulse produced when even a small nuclear bomb is detonated at high altitudes — is Packer's biggest worry. In less than a second, the pulse can melt the wires of every piece of solid-state electronics, and the entire electrical system, in the United States.

Likelihood is increasing