Skip to main content

The making of a nightmare tornado

By Louis Wicker, Special to CNN
May 22, 2013 -- Updated 1126 GMT (1926 HKT)
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
August 22, 2014 -- Updated 1231 GMT (2031 HKT)
James Dawes says calling ISIS evil over and over again could very well make it harder to stop them.
August 22, 2014 -- Updated 1223 GMT (2023 HKT)
Retired Lt. Gen. Mark Hertling says he learned that the territory ISIS wants to control is amazingly complex.
August 21, 2014 -- Updated 1450 GMT (2250 HKT)
David Weinberger says Twitter and other social networks have been vested with a responsibility, and a trust, they did not ask for.
August 22, 2014 -- Updated 1103 GMT (1903 HKT)
John Inazu says the slogan "We are Ferguson" is meant to express empathy and solidarity. It's not true: Not all of us live in those circumstances. But we all made them.
August 20, 2014 -- Updated 1951 GMT (0351 HKT)
Cerue Garlo says Liberia is desperate for help amid a Ebola outbreak that has touched every aspect of life.
August 21, 2014 -- Updated 1742 GMT (0142 HKT)
Eric Liu says Republicans who want to restrict voting may win now, but the party will suffer in the long term.
August 21, 2014 -- Updated 1538 GMT (2338 HKT)
Jay Parini: Jesus, Pope and now researchers agree: Wealth decreases our ability to sympathize with the poor.
August 21, 2014 -- Updated 1200 GMT (2000 HKT)
Judy Melinek offers a medical examiner's perspective on what happens when police kill people like Michael Brown.
August 19, 2014 -- Updated 2203 GMT (0603 HKT)
It used to be billy clubs, fire hoses and snarling German shepherds. Now it's armored personnel carriers and flash-bang grenades, writes Kara Dansky.
August 20, 2014 -- Updated 1727 GMT (0127 HKT)
Maria Haberfeld: People who are unfamiliar with police work can reasonably ask, why was an unarmed man shot so many times, and why was deadly force used at all?
August 18, 2014 -- Updated 2152 GMT (0552 HKT)
Ruben Navarrette notes that this fall, minority students will outnumber white students at America's public schools.
August 19, 2014 -- Updated 2121 GMT (0521 HKT)
Humans have driven to extinction four marine mammal species in modern times. As you read this, we are on the brink of losing the fifth, write three experts.
August 19, 2014 -- Updated 1158 GMT (1958 HKT)
It's been ten days since Michael Brown was killed, and his family is still waiting for information from investigators about what happened to their young man, writes Mel Robbins
August 18, 2014 -- Updated 1242 GMT (2042 HKT)
The former U.K. prime minister and current U.N. envoy says there are 500 days left to fulfill the Millennium Goals' promise to children.
August 20, 2014 -- Updated 1738 GMT (0138 HKT)
Peter Bergen says the terror group is a huge threat in Iraq but only a potential one in the U.S.
August 18, 2014 -- Updated 2006 GMT (0406 HKT)
Pepper Schwartz asks why young women are so entranced with Kardashian, who's putting together a 352-page book of selfies
ADVERTISEMENT