tornadoes

New Information Turns Theory Upside Down, Or Does It?

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It seems that recent research has come up with information that may be surprising to many, particularly those in the non-scientific community, but not me.  That came from a December 17th article in physics.org titled “New research finds tornadoes form from the ground up, contrary to popular thought.” written by Lauren Lipuma, from the American Geophysical Union. Here’s how the article began. “Historically, scientists assumed tornado rotation began in storm clouds, creating a funnel that travels downwards. This theory matches what storm chasers observe visually in the field. Viewers often report seeing funnel clouds gradually descending until they make contact with the ground.” Now we get to the point of the article. “But new research combining a new type of Doppler radar with photos and videos of tornadoes formed by supercell thunderstorms shows the opposite is true: Tornadoes materialize from the ground up.”

The way it has been since I got into the weather business in the early 70s is that tornadoes or their rotation were spotted up in the sky and often found on radar or when they started chewing up the ground causing destruction and then warnings were issued. What follows is a definition and tornado formation information.

Here is how the National Weather Service defines the term tornado. “A tornado is a violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground. It nearly always starts out as a funnel cloud and may be accompanied by a loud roaring noise. On a local scale, it is the most destructive of all atmospheric phenomena.”

Tornado
Tornado Structure | Image by bbs.wenxuecity.com

They need certain elements to form including warm moist airflow from the south, cooler drier air from the north and a rotation that begins when a mesocyclone is formed. A mesocyclone is defined as a “storm-scale region of rotation, typically 2-6 miles in diameter and often found in the right rear flank of a supercell.” The mesocyclone’s circulation is much larger than the tornado circulation that can develop within it. Research I have seen over the years has shown the tornado funnel itself can build in various stages sometimes starting high in the sky and dropping down to the ground or building from the ground level upward, ore even from mid-levels expanding both upward and downward. Remember the difference between a funnel cloud and a tornado? The funnel cloud has the vortex rotation but is not touching the ground. In order for a funnel cloud to be called a tornado it must reach the ground.

Man-made Tornado
T. Ted Fujita Developed First Laboratory-made Tornado | Image by slideplayer.com

The way the wind speeds rotating around a tornado vortex are calculated was originally devised by the late Dr. Tetsuya Theodore Fujita who worked out of the University of Chicago in Illinois. The scale went from F-0 to F-5 with F-0 being the weakest causing minor damage and F-5 being the strongest causing total destruction.

EF Scale
Enhanced Fujita-Pearson Tornado Scale | Image by smokeys-trail.com

The scale has been updated (February 2007) and improved and is now called the Enhanced Fujita-Pearson Scale. According to Pearson the reasons for the updating of the scale are “that tornado wind speeds required to inflict the described damage were actually much lower than the F-Scale indicated, particularly for the upper categories. Also, though the scale gave general descriptions of the type of damage a tornado could cause, it gave little leeway for strength of construction and other factors that might cause a building to receive higher damage at lower wind speeds.”

El Reno Twister
El Reno, OK Tornado 5/31/13 | Photo by National Weather Service

Now back to the latest research. The El Reno tornado, which occurred on May 31, 2013 in central Oklahoma, was a record breaker. It’s winds were clocked at 300 miles per hour, the second highest wind speeds recorded on Earth, and at 2.6 miles in diameter it was the widest tornado ever recorded. As luck would have it a research team was at the site of the outbreak with all of their equipment. Meteorologist Jana Houser, from Ohio University at Athens led the team.

Houser & Radar
Jana Houser With Mobile Radar Truck | Photo From Jana Houser

“Houser and a team of researchers from the University of Oklahoma happened to be monitoring the storm with a new type of mobile Doppler radar system that collected tornado wind speeds every 30 seconds.

Anton Seimon
Anton Seimon, Geographer Appalachian State U. | Photo by Appalachian State University

Afterwards, Anton Seimon, a geographer at Appalachian State University in Boone, North Carolina who had chased the El Reno storm, collected hundreds of still photos videos of the epic twister from citizens and fellow storm chasers.” Comparing the the pictures with her low-level radar data Houser found the photos showed the tornado funnel at ground level several minutes before it was seen on the radar. She studied four data sets and all indicated the development from the ground up.

Jana Houser presented her findings at the American Geophysical Union’s Fall meeting. She feels her research indicates that the forecasters need to chance the current priority of paying attention to the upper rotation and be more concerned with the ground-level rotation in order to make better tornado predictions.

It will be very interesting to see how the meteorological community reacts to the latest data and what steps might be taken to improve tornado forecasting and detection methods.

Let me know what you would like me to talk about or explain. You can email me at: [email protected].

Introducing The “Father Of Tornado Research.”

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I have discussed tornadoes in previous articles and mentioned the man most responsible for just about everything we know today about these destructive and deadly cyclones. His name is Tetsuya Theodore Fujita, also known as Ted Fujita or T. Theodore Fujita. It is, to say the least, interesting to research his background.

Close-up Fujita
T. Theodore Fujita (close-up) With His F-Scale | Image by slideplayer.com

Britannica.com explains that Fujita was born in 1920 in Kitakyushu, Japan. This is only a snippet of his biography. He earned a bachelors degree in mechanical engineering from Meiji College of Technology in Tokyo. In 1944 he was an assistant physics professor in the college’s physics department. After completing his doctoral degree in 1953 he emigrated to the United States to work at the University of Chicago in their meteorology department. In 1968 he became a U.S. citizen and continued working at the University of Chicago until his death on November 19,1998.

Man-made Tornado
T. Ted Fujita Developed First Laboratory-made Tornado | Image by slideplayer.com

His research brought to the scientific community a better understanding of how tornadoes form and the power they contain. Fujita was the first to develop a way to make a tornado in a lab to study it up close. He was the first to put forth the theory and then prove that tornadoes can form in a “family” meaning multiple tornadoes developing from the same wall cloud and later research showed that, as an example, three tornadoes could form from one parent twister then separate and cause damage, then rejoin as one funnel and continue on its path.

Palm Sunday Outbreak
1965 Palm Sunday Outbreak | Image by sahs.us

Dr. Fujita studied the aftermath of a large-scale tornado outbreak, called the Palm Sunday Outbreak, that occurred on April 11th & 12th in 1965. The series of tornadoes ripped through 6 states including Ohio, Michigan, Indiana, Illinois, Wisconsin, and Iowa. The outbreak resulted in 270 deaths with at least 5,000 persons injured and an estimated $250 million in damage. He was, here it comes again, the first to use extensive airborne photos of the damage and debris field to analyze the tornado paths and developed his “Fujita Scale” or F-Scale based on his interpretation of the angles of twisted debris to estimate the actual speed of the rotating vortex winds.

Fujita's Contributions
Fujita’s Contributions | Image by NWS Grand Rapids via Twitter

Quoting the Britannica.com “The capstone of Fujita’s work with tornadoes is considered by many to be his work with the super outbreak of April 3-4, 1974, a national-scale outbreak of 148 tornadoes (4 of the tornadoes were later reclassified as downbursts by Fujita). His maps of complex damage patterns aided his identification of previously undiscovered phenomena, the downburst and the microburst. These sudden, severe downdrafts can result in 250-km (150 mile-) per-hour winds on or near the ground that often uproot trees in discernible starburst patterns.” His theory was met with skepticizm by the scientific community until he showed that a 1975 airliner crash at Kennedy Airport in New York City was  caused my microbursts.

Thunderstorm Downburst
Thunderstorm Downburst Explained | Image by NOAA.gov through slideserve

When there has been damage that could have been caused by either a tornado or a downburst the National Weather Service sends an expert to discern which was the culprit. The tornado’s winds rotate around forming the spinning vortex while the downburst can come straight down from the cloud base or plummet at an angle to the ground. The tornado debris lays out in twisted formations while the downburst debris is either flattened vertically forming a starburst pattern or spread laterally striking trees, buildings, etc. flattening them in astraight line. They also look for drag marks on the ground which would be made by a tornado not a downburst. Aerial photographs are also used, as previously mentioned, and can make these patterns show up even more prominently.

F-Scale vs EF-Scale
Fujita F-Scale/Enhanced EF-Scale | Image by youtube.com

Fujita’s F-Scale was revised in by a team of meteorologists and became known as The Enhanced Fujita Scale (EF-Scale). The National Weather Service adopted the EF-Scale in 2007 and Environment Canada (the Canadian National Weather Service) started using it in 2013.

The University of Chicago
The University of Chicago | Image by Gary/Chicago Crusader

I think I mentioned in a previous article that I actually had contact with Dr. Fujita many years ago. I was working on an independent study research project at Memphis State University (now the University Of Memphis) and part of my project included listing and mapping severe thunderstorm and tornado events over a 30-year period for a 33-county area surrounding Memphis. I needed a map showing the tornado occurrences over the whole continental U.S. for comparison and contacted his office at the University of Chicago. I spoke with one of his associates who sent the map to me after one telephone call. When my research was completed I needed some more information to compare the peak month of tornado activity in my area at the time with that of the whole country. Dr. Fujita had just released his book delineating the history of tornadoes in the U.S. and I needed some clarification to make my conclusions. I placed the second call expecting to talk with one of his assistants again, but was very surprised when he answered the phone. He was very cordial and proceeded to give me all of the information I needed. I really wish I could have been able to actually meet him in person.

Believe it or not, Fujita did most of his research and made most of his discoveries without having even seen a tornado up close. To remedy that he decided to go with the Storm Chasers in the field ( I believe in the 1970s) so he could witness the power of the tornado first hand.

Oregon Tornado Damage
Aumsville, OR EF-2 Tornado 12/14/2010 | Photo by The National Weather Service

We average only one tornado a year in the whole state of Oregon, but that doesn’t mean you shouldn’t be prepared to protect yourself if one drops down near you.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

Dorothy Couldn’t Get To Oz Without One.

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They have been both a mystery and a curse to most people, especially those living in the “alley.” The alley I am talking about is “Tornado Alley.” The area of the United States most prone to being ravaged by tornadoes. Actually tornadoes can and have occurred in all 50 of the United States. There have been some recent tornado events that resulted in death and destruction. Thursday April 3rd a powerful storm ripped through the central US causing serious damage but no known fatalities. At around 7:00 pm Central Daylight Time a damaging twister with quarter-sized hail was reported near Washington, Missouri. A tornado was spotted about 50 miles to the east at 8:16 pm near Glendale, Missouri. That same day a tornado was reported to have touched down south of Krum in Denton County, Texas. Talk about strange, exactly 40 years ago 148 reported tornadoes killed 330 people over 143 states. Two people were killed and twenty were injured due to severe weather Monday April 7th. A tornado touched down in Beaufort County, North Carolina. All of this storm and tornado activity happened in the span of only one week.

We know that tornadoes exist and that they both kill and cause serious damage. Let’s take a look at how these twisters are formed. Here is how the National Weather Service defines the term tornado. “A tornado is a violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground. It nearly always starts out as a funnel cloud and may be accompanied by a loud roaring noise. On a local scale, it is the most destructive of all atmospheric phenomena.”

Tornado Structure | Image by bbs.wenxuecity.com
Tornado Structure | Image by bbs.wenxuecity.com

They need certain elements to form including warm moist airflow from the south, cooler drier air from the north and a rotation that begins when a mesocyclone is formed. A mesocyclone is defined as a “storm-scale region of rotation, typically 2-6 miles in diameter and often found in the right rear flank of a supercell.” The mesocyclone’s circulation is much larger than the tornado circulation that can develop within it. Here is a video that shows a way the mesocyclone winds can spin into a tornado funnel. Research I have seen over the years has shown the tornado funnel itself can build in various stages sometimes starting high in the sky and dropping down to the ground or building from the ground level upward. Remember the difference between a funnel cloud and a tornado? The funnel cloud has the vortex rotation but is not touching the ground. In order for a funnel cloud to be called a tornado it must reach the ground.

Movie "Twister" | Image by drafthouse.com
Movie “Twister” | Image by drafthouse.com

There have been many movies made featuring tornadoes, but the most accurate depiction I have ever seen was “Twister.” I found two flaws in the details however. First of all if you are in a red Dodge Ram pickup truck you will be safe. At least it happened that way until the end of  the movie. That’s more tongue-in-cheek. The other flaw, if you will, is that the characters get all excited when one of them announces what they on the radio that they have an F-3 tornado on the ground. You can’t assign the number until after the tornado has passed and a lengthy ground check has been made and possibly even an aerial view has been examined. They should have said a possible F-3. Later on they say the weather service is predicting an F-5 tornado. That is what they would have said since the two cells were merging and they would very possibly create a massive F-5 tornado.

Enhanced Fujita-Pearson Tornado Scale | Image by smokeys-trail.com
Enhanced Fujita-Pearson Tornado Scale | Image by smokeys-trail.com

The way the wind speeds rotating around a tornado vortex are calculated was originally devised by the late Dr. Tetsuya Theodore Fujita who worked out of the University of Chicago in Illinois. The scale went from F-0 to F-5 with F-0 being the weakest causing minor damage and F-5 being the strongest causing total destruction. The scale has been updated (February 2007) and improved and is now called the Enhanced Fujita-Pearson Scale. The reasons for the updating of the scale are “that tornado wind speeds required to inflict the described damage were actually much lower than the F-Scale indicated, particularly for the upper categories. Also, though the scale gave general descriptions of the type of damage a tornado could cause, it gave little leeway for strength of construction and other factors that might cause a building to receive higher damage at lower wind speeds.”

Aumsville, OR EF-2 Tornado 12/14/2010 | Photo by The National Weather Service
Aumsville, OR EF-2 (cold core) Tornado 12/14/2010 | Photo by The National Weather Service

The whole state of Oregon averages over time about three tornadoes per year. From 1950 through 1995 there were 50 reported tornadoes in the state. Most were F-0 or F-1 in strength.  The type we see are called “cold core tornadoes.” The rising of very warm moist air into the higher reaches of the atmosphere is what gives tornadoes their strength. We rarely get very warm air and high relative humidity at the same time, so what happens here is the cold air aloft dives down to meet the warmer air. Simply put, shortening that distance makes a weaker tornado that, here in Oregon, usually causes very little damage and has resulted in no deaths or injuries during that 45-year period.

Believe it or not the best way we have to spot tornadoes is for people who see them to call the authorities and report the location and direction of movement. Doppler Radar is an amazing tool for helping to spot and track tornadoes. For a detailed explanation of how Doppler Radar works check out my previous column called “Doppler What?” If you see a tornado you need to take shelter immediately and once you are in a safer place call 911 and report it.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].