NORMAN — In February, Louis Uccellini was named the National Oceanic and Atmospheric Administration's assistant administrator for weather services and director of the National Weather Service. Uccellini is responsible for the day-to-day civilian weather operations for the United States, its territories, adjacent waters and ocean areas.
Uccellini was in Oklahoma recently. On Nov. 3, David Andra, meteorologist in charge of the National Weather Service's Norman Forecast Office, took Uccellini to see some of the areas affected by the May 20 tornado. Then on Monday and Tuesday, Uccellini met with weather service employees in Norman. During his visit, he talked with The Oklahoman about what he takes from his tour and about decisions regarding the change in the enhanced Fujita rating of the May 31 El Reno-area tornado.
Q: In recent days, you toured portions of Moore that were struck by the EF5 on May 20. Although it's been more than five months, what did you see? What is something that really affected you?
A: Even though it was five months and there has been a lot of clean up that has happened, buildings taken down that were severely damaged, the magnitude of the event was still starkly visible — the width of the damage, the length of the damage. We were in a certain area where you could look either direction down the track and there was basically nothing there. Dave (Andra) emphasized this was an entire neighborhood, there were houses there, it wasn't empty fields.
We went to the elementary school where the seven children were killed. It was really a tragic reminder of what happened.
We were standing next to the hospital where they've cleared the ground. It's a great story in the sense of the decisions that were made, the connections that were made to the weather service beforehand. There were decisions that were made by the hospital administrators, the preparation that they had gone through. So, you get the entire spectrum from the sheer magnitude, the tragedy that unfolded and then the fact that the system worked, that it could have been so much worse if we didn't have an effective warning program and if we didn't have an effective way of reaching out to people who organize the decision process that helps save lives and mitigate property loss.
Q: The May 31 El Reno-area tornado was first categorized as an EF3 on the enhanced Fujita scale based on structural damage observed. It was changed a few days later to an EF5 based on radar information. Then it was returned to an EF3 rating. Please talk about that decision.
A: We have an impact scale, established to measure the magnitude or infer the magnitude of a tornado based on the damage at the ground. This has been carefully researched, carefully applied across the country
The engineering studies have been done that show what a wind speed would need to be to create the kinds of damage that we see.
You can take that standard and you can apply it anywhere across the country. So, we've adopted that standard. It's a very important measure. There are all kinds of building and insurance aspects that are based upon us applying this type of a scaling to the damage and inferring the wind speeds that existed with the tornado at the ground.
So when you now introduce a new observing system, and you're measuring wind speeds 500 feet above the ground, and it's a larger wind speed than was inferred at the ground, there's been an inclination to say, ‘OK well let's use that wind speed instead of the one that's inferred at the ground.'
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