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 12:53 PM EDT, Tue September 30, 2014
Jeff Yang calls Ello a wakeup call to Facebook and Twitter, and a sign of hope for fast-rising upstarts Pinterest and Snapchat.
updated 10:23 AM EDT, Wed October 1, 2014
Paul Waldman says the Secret Service should examine its procedures to make sure there are no threats to the White House--but without losing the openness so valuable to democracy
updated 10:25 AM EDT, Wed October 1, 2014
Jesse Williams says the videotape and 911 call that resulted in police gunning down John Crawford at a Walmart reveals the fatal injustice of racial assumptions
updated 7:03 PM EDT, Tue September 30, 2014
Mel Robbins says officials should drop the P.C. pose: The beheading in Oklahoma was not workplace violence. Plenty of evidence shows Alton Nolen was an admirer of ISIS.
updated 3:11 PM EDT, Tue September 30, 2014
The Occupy Central movement has already achieved much by bringing greater attention to Hong Kong's struggle for democracy, William Piekos says..
updated 3:11 PM EDT, Tue September 30, 2014
The Occupy Central movement has already achieved much by bringing greater attention to Hong Kong's struggle for democracy, writes William Piekos.
updated 10:13 AM EDT, Tue September 30, 2014
As Prime Minister Narendra Modi visits America, Madeleine Albright says a world roiled by conflict needs these two great democracies to commit to moving their partnership forward
updated 10:04 AM EDT, Tue September 30, 2014
John Sutter: Lake Providence, Louisiana, is the parish seat of the "most unequal place in America." And until somewhat recently, the poor side of town was invisible on Google Street View.
updated 9:11 AM EDT, Mon September 29, 2014
Julian Zelizer says in the run up to the 2016 election the party faces divisions on its approach to the U.S.'s place in the world
updated 10:19 AM EDT, Mon September 29, 2014
Ruben Navarrette says Common Core supporters can't devise a new set of standards and then fail to effectively sell it.
updated 9:29 AM EDT, Tue September 30, 2014
Earlier this month, Kenyans commemorated the heinous attack on the Westgate Mall in Nairobi.
updated 2:59 PM EDT, Tue September 30, 2014
David Wheeler says Colorado students are right to protest curriculum changes that downplays civil disobedience.
updated 9:58 PM EDT, Fri September 26, 2014
Sally Kohn says when people click on hacked celebrity photos or ISIS videos, they are encouraging the bad guys.
updated 7:55 AM EDT, Fri September 26, 2014
Loren Bunche says she walked by a homeless man every day and felt bad about it -- until one day she paused to get to know him
updated 9:32 AM EDT, Tue September 30, 2014
ISIS grabs headlines on social media, but hateful speech is no match for moderate voices, says Nadia Oweidat.
updated 8:33 AM EDT, Mon September 29, 2014
A new report counts jihadists fighting globally. The verdict? The threat isn't that big, says Peter Bergen.
updated 5:37 PM EDT, Tue September 23, 2014
Ebola could become the biggest humanitarian disaster in a generation, writes former British Prime Minister Tony Blair
updated 12:58 PM EDT, Fri September 26, 2014
ISIS has shocked the world. But will releasing videos of executions backfire? Four experts give their take.
updated 10:39 AM EDT, Fri September 26, 2014
Eric Holder kicked off his stormy tenure as attorney general with a challenge to the public that set tone for six turbulent years as top law-enforcement officer.
updated 9:09 AM EDT, Fri September 26, 2014
LZ Granderson says Obama was elected as a war-ending change agent, not a leader who would leave behind for his successor new engagement in Iraq and Syria. Is he as disappointed as the rest of us?
updated 5:10 AM EDT, Wed September 24, 2014
Gayle Lemmon says the question now is how to translate all the high-profile feminizing into real gains for women
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT