Remembering Moore
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Just three years ago, on May 3rd, one of the biggest, most devastating tornado outbreaks in the United States, zoned in on central Oklahoma.

Hi, I'm Bryan Yeaton for The Weather Notebook.

Daphne Zaras is a research meteorologist for the National Severe Storms Lab in Norman, Oklahoma. She was out with a team of researchers on that day.

DZ: That was our first operation day, May 3 was ,for 1999, and we were thinking there might be a tornado or two that morning, and that we would go and make sure everything worked properly. It turned out that there were quite a few tornadoes that day, and we ended up getting some pretty valuable data for the research that we're doing.

How do they know a storm has tornadic potential?

DZ: We're looking, just to have thunderstorms at all‹there's instability in the atmosphere‹but then you want those thunderstorms to rotate, to become supercells. So, for that you're looking for wind shear‹the winds turning with height, especially in the lowest few kilometers of the atmosphere.

These were the conditions on May 3rd.

DZ: The storm that hit Moore on May 3 ended up tracking for several hours. It started south of the Witchita Mountains in southwest Oklahoma, and dissipated shortly after it went through Oklahoma City.

Seventy-one tornadoes struck Oklahoma and Kansas that day, and 44 people lost their lives.

DZ: One of our scientists at the National Severe Storms Lab did a study looking at how many homes were destroyed, and how many people typically die given the number of homes destroyed. And what he found was, given the number of homes destroyed‹and this is the insurance company kind of destroyed‹he estimates that as many as 684 people might have lost their life.

The Weather Notebook is produced at the Mount Washington Observatory, and generously supported by Subaru and the National Science Foundation.