Skip to main content

The making of a nightmare tornado

By Louis Wicker, Special to CNN
updated 7:26 AM EDT, Wed May 22, 2013
A message is left by a homeowner who lost his home in the May 20 tornado on Monday, May 27, in Moore, Oklahoma. <a href='http://www.cnn.com/2013/05/20/us/gallery/midwest-weather/index.html'>View more photos of the aftermath in the region</a> and another gallery of <a href='http://www.cnn.com/2013/05/21/us/gallery/oklahoma-tornado-aerials/index.html'>aerial shots of the damage</a>. A message is left by a homeowner who lost his home in the May 20 tornado on Monday, May 27, in Moore, Oklahoma. View more photos of the aftermath in the region and another gallery of aerial shots of the damage.
HIDE CAPTION
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
Deadly tornado hits Oklahoma City area
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
>
>>
STORY HIGHLIGHTS
  • Author: Hard to fathom three major tornado events have hit Moore, Oklahoma, in 14 years
  • He says it's not unusual for an extreme tornado to strike the Midwest
  • A tornado can form when a sharp updraft meets faster winds of the jet stream
  • Predictions have improved, but research may yield further advances, he says

Editor's note: Louis Wicker is a research meteorologist at NOAA's National Severe Storms Laboratory in Norman, Oklahoma.

Norman, Oklahoma (CNN) -- On Tuesday morning, the residents of Moore, Oklahoma, woke again to another nightmare.

In the past 14 years, Moore and its nearby neighbors have been subjected to devastation from three major tornado events.

The latest chapter in this nearly unimaginable history was the EF5 tornado that claimed the lives of 24 people and injured hundreds. But how unusual is this tornado in context?

While the frequency is unusual, especially over such a short period, the actual tornado is less of an anomaly. Over the same 14 years, there were a number of similar events.

The Joplin, Missouri, tornado of May 22, 2011, destroyed 25% of the town and killed 158 people. The path length for the Joplin tornado was similar in length and width, about 20 miles long and 1.5 miles wide.

The "original" Moore tornado on May 3,1999, was rated F5 (NOAA now uses the enhanced Fujita scale, called the "EF" scale). It killed 36 people in Moore and had a similar path length.

On April 27, 2011, fifteen EF4 and EF5 tornadoes tracked across Mississippi and Alabama -- many having damage tracks that extended for dozens of miles.

So while horrible and sad, this extreme class of tornado occurs regularly in the United States. And when these tornadoes travel across populated areas, we see their awesome power at its worst.

Inside a personal tornado shelter
CNN iReporter steps in to rescue victims
Moore mayor on school safety in tornadoes
Storm chaser: I was in a shock

So what do we know about the conditions that cause these violent storms?

First, the atmosphere must be what is called potentially unstable. Potentially means the atmosphere must first build up heat and moisture near the ground, like fueling the gas tank of your car for a long trip.

Unstable means that if an imaginary balloon filled with air from near the ground were to be lifted upward, colliding with some weather feature such as a cold front, the "balloon" would become warmer than the surrounding air at that level. The initial "push" upward by the cold front on that balloon filled with surface air is like a child letting a helium-filled balloon go -- it just keeps rising.

The difference is that on these violent tornado days, the balloon does not just rise in a leisurely way. It slingshots upward, especially when the air inside cools enough to condense all the water vapor it carries.

It's the extra heat released when the water vapor condenses that is like a driver flooring a car's accelerator. The balloon of surface air quickly reaches speeds of 100 to 150 mph going straight up!

Our "balloons" -- meteorologists call them "updrafts" -- are the engines of the storm. The energy released in the updrafts then interacts with our second ingredient needed for violent tornadoes, the change of the wind direction and speed at you go upward from the ground.

Anyone who has flown knows that the wind speed increases with height. These violent storms almost always require that the wind speeds increase from 20 mph on the ground to more than 100 mph (horizontally) aloft.

Spin in the storm's updraft is enhanced when the air entering the base of the updraft is from the south, while the winds further aloft are flowing from west to east. This is the so-called jet stream, the fast river of air that helps drive our weather, which interacts with the storm's updrafts to create a spinning column of air.

It is this updraft spin, or mesocyclone, that creates the tornado.

When the updrafts are strong and the wind shear large, the spin inside the mesocyclone becomes very fast. And in the most extreme cases, a violent tornado is born beneath that spinning white cloud of updraft that meteorologists call the supercell thunderstorm.

So how well can we predict these storms?

Tornado deaths during the past 50 years have declined considerably, indicating our forecasting and warning skill has improved considerably.

The deployment of the Doppler radar system in the early 1990s by the National Oceanic and Atmospheric Administration extended tornado warning lead times from five minutes to their now-annual average of 12 to 14 minutes. But other factors have improved warnings as well since then.

During the past 20 years, supercell thunderstorms have been the focus of intense academic and government research to understand how they work and how they produce tornadoes.

Two major field programs have studied these storms using dozens of mobile weather stations, aircraft and Doppler radars. The result from all these years of research and training was displayed Monday. Forecasters from the National Weather Service Office in Norman, Oklahoma, were very aware that the atmosphere in and around central Oklahoma had all the ingredients for significant tornadoes.

Knowing that the atmosphere could produce a strong tornado, they immediately issued the tornado warning as soon as the Doppler radar started to show low-level rotation within the storm.

This warning was 16 minutes before the touchdown of the Moore tornado outside of Newcastle, Oklahoma, and nearly an hour before the end of the tornado some 20 miles away.

Undoubtedly, the long lead time saved countless lives. I'm one of a number of researchers at NOAA who are working on ways to combine all of the environmental, radar and other weather data into a computer model that will attempt to predict when the tornado will develop and how strong it will be as much as an hour in advance.

This "Warn on Forecast" concept, while showing promise, is still years away from being a reality.

So until then, when you hear the tornado sirens or tornado warning, take cover immediately. Like the people in Moore, your life may depend on it.

Follow us on Twitter @CNNOpinion

Join us on Facebook/CNNOpinion

The opinions expressed in this commentary are solely those of Louis Wicker.

ADVERTISEMENT
Part of complete coverage on
updated 6:47 PM EDT, Tue April 22, 2014
Q & A with artist Rachel Sussman on her new book of photographs, "The Oldest Living Things in the World."
updated 3:58 PM EDT, Tue April 22, 2014
Martin Blaser says the overuse of antibiotics threatens to deplete our bodies of "good" microbes, leaving us vulnerable to an unstoppable plague--an "antibiotic winter"
updated 1:37 PM EDT, Tue April 22, 2014
John Sutter asks: Is it possible to eat meat in modern-day America and consider yourself an environmentalist without being a hypocrite?
updated 11:38 AM EDT, Tue April 22, 2014
Sally Kohn notes that Meb Keflezighi rightly was called an American after he won the Boston Marathon, but his status in the U.S. once was questioned
updated 8:56 AM EDT, Tue April 22, 2014
Denis Hayes and Scott Denman say on this Earth Day, the dawn of the Solar Age is already upon us and the Atomic Age of nuclear power is in decline
updated 4:36 PM EDT, Mon April 21, 2014
Retired Coast Guard officer James Loy says a ship captain bears huge responsibility.
updated 1:08 PM EDT, Mon April 21, 2014
Peter Bergen says the latest strikes are part of an aggressive U.S. effort to target militants, including a bomb maker
updated 9:45 AM EDT, Mon April 21, 2014
Cynthia Lummis and Peter Welch say 16 agencies carry out national intelligence, and their budgets are top secret. We need to know how they are spending our money.
updated 8:35 AM EDT, Mon April 21, 2014
Julian Zelizer says President Obama knows more than anyone that he has much at stake in the midterm elections.
updated 8:55 AM EDT, Tue April 22, 2014
Eric Sanderson says if you really want to strike a blow for the environment--and your health--this Earth Day, work to get cars out of cities and create transportation alternatives
updated 10:08 AM EDT, Mon April 21, 2014
Bruce Barcott looks at the dramatic differences in marijuana laws in Colorado and Louisiana
updated 4:47 PM EDT, Fri April 18, 2014
Jim Bell says NASA's latest discovery supports the notion that habitable worlds are probably common in the galaxy.
updated 2:17 PM EDT, Fri April 18, 2014
Jay Parini says even the Gospels skip the actual Resurrection and are sketchy on the appearances that followed.
updated 1:52 PM EDT, Fri April 18, 2014
Graham Allison says if an unchecked and emboldened Russia foments conflict in a nation like Latvia, a NATO member, the West would have to defend it.
updated 9:11 AM EDT, Fri April 18, 2014
John Sutter: Bad news, guys -- the pangolin we adopted is missing.
updated 2:25 PM EDT, Mon April 21, 2014
Ben Wildavsky says we need a better way to determine whether colleges are turning out graduates with superior education and abilities.
updated 6:26 AM EDT, Fri April 18, 2014
Charles Maclin, program manager working on the search and recovery of Malaysia Flight 370, explains how it works.
updated 8:50 AM EDT, Fri April 18, 2014
Jill Koyama says Michael Bloomberg is right to tackle gun violence, but we need to go beyond piecemeal state legislation.
updated 2:45 PM EDT, Thu April 17, 2014
Michael Bloomberg and Shannon Watts say Americans are ready for sensible gun laws, but politicians are cowed by the NRA. Everytown for Gun Safety will prove the NRA is not that powerful.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT