Tornadoes

A tornado is a vortex and may also contain vortices. A vortex is a rotating body of liquid or gass. In a tornado, the vortex is made visible by condensation or dust and debris. It may look like a cone, tapering appendage, or column attatched to the clouds, or may take the appearance of a tube or swirling mass of dust.

Except in the most violent tornadoes, structures generally are not blown away unless they are weak or poorly anchored, though they may still be destroyed. Banks are generally very sturdy structures. To blow a bank away would require a tornado of EF5 intensity, the highest rating possible. Tornadoes this strong are very rare. Since the new scale went into effect in 2007, 9 tornadoes have been rated EF5. Three of those tornadoes struck banks, and only one of those banks was hit by the full force of the tornado.

The first case was in Parkersburg, Iowa on May 25, 2008. The worst part of the tornado missed the bank, which was badly damaged, but remained standing.

The second case was in Joplin, Missouri on May 22, 2011. The bank was destroyed with all exterior walls swept away; only the vault remained in place.

The third case was in Moore, Oklahoma on May 20, 2013. The Federal Credit Union was demolished, with only the vault left intact.

The negative economic effects of a tornado are mostly local. When a major tornado strikes a city, the cost of damage and repairs can be enormous. There is also a cost of lost productivity as workplaces and businesses are destroyed or forced to close for repairs and as potentially hundreds are injured. Many people may not be willing to rebuild and will move elsewhere.

While there are some general things that happen while a tornado is approaching, a storm may not necessarily have these characteristics, as there is a great deal of variability in how a tornadic storm can behave.

Most tornadoes occur in the rear portions of thunderstorms. As a tornado is approaching you will often experience thunder, lightning, and very heavy rain. Hail, potentially very large, may also be present. In many cases before the tornado hits, the rain will stop, and there will be an eerie stillness. The sky may appear gray, black, green, or yellow. You may see the tornado itself, looking, perhaps, like an enormous elephant trunk or cone, or sometimes a whirling mass of dust and debris. The clouds around it may rapidly rotate. Sometimes, however, the rain does not stop, and the tornado is never seen, and then is suddenly upon you. Reports on the sound that people hear near a tornado vary. The classic description says that a tornado has a low roar like a freight train. Others have compared the sound to a jet engine or a waterfall. Still others have said that the sound was indescribable, unlike anything they had ever heard.

Tornadoes are commonly known for tearing swaths of destruction through communities.

Tornadoes can cause a sginificant disruption. When a warning is issued people must take cover. Afterward, people must repair or rebuild. In some cases search and rescue parties must be formed.

No. Tornado activity fluctuates from one year to the next. Looking at the number of recorded tornadoes, there appears to have be an increase though the 20th century, but this is entirely due to our increased ability to detect F0 and F1 tornadoes. The number of significant (F2 and stronger) tornadoes in recent years is actually somewhat lower than it was in the 1950s and 1960s.

While 2011 was the most violent year for tornadoes in decades, 2012 and 2013 saw some of the lowest overall tornado activity since the late 1980s.

Yes. Any location in North Dakota can have tornadoes. Willston was struck by a weak tornado in 1977, but has otherwise been lucky.

In the region known as "Tornado Alley," (Norman, Okahoma) is located the NSSL (the National Severe Storm Laboratory) the organization that study tornadoes. The NSSL focuses its action in three areas:

Radar research and development. It includes initiatives such as weather radar, dual-polarized Doppler radar, and the National Weather Radar Testbed. It's an agency working to advance the development of new radar technologies, aiming integrated observations, predictions, and warnings of high-impact weather, which include tornadoes, heavy thunderstorms, and flash floods.

Hazardous weather research. (Improves accuracy and amount of lead time of forecasts and warnings issued by the National Weather Service. )

Hydrometeorology research. Improves the work of the NWS's monitoring and predictions of floods and flash floods.

The whole information is accessible by opening the related link below.

Surveys to count and rate tornadoes are conducted by local offices of the National Weather Service. Records of tornado activity are kept by the Storm Prediction Center and National Climatic Data Center.

There were more than 120 recorded tornadoes in Texas in 1970. Most were not particularly damaging, but several were very destructive. On the evening of April 17 an F4 tornado struck Plainview, killing 5 people and injuring 51. THen, just after midnight on April 18, a second F4 struck Clarendon, killing 16 people injuring 42. The most significant event cam on May 11, when an F5 tornado struck Lubbock, killing 26 people and injuring more than 500. Adjusting for inflation, the damage amounted to more than $800 million in modern amounts, making it one of the costliest tornadoes in U.S. history. Through detailed analysis of the damage from this tornado, Tetsuya Fujita devloped the Fujita scale, which went into effect in 1971.

The warning, which was actually more like a tornado watch, was issued by the United States Air Force. At the time, the Weather Bureau, the precursor to the National Weather Service, forbade the mentioning of tornadoes in its forecasts.

The safest thing to do is to go to an underground shelter such as a basement or cellar.

Since official records began in 1950 Stephenville has been hit by 4 tornadoes. 3 were rated F0 and 1 was rated F2.

All cities in Oklahoma are in Tornado Alley. Oklahoma City is in the most intense part of it.

Damage estimates range from $50,000 to $200,000 in 1902 values. In today's amounts that is equivalent to about $1.3-5.3 million

The main part of the circulation of a tornado when the strongest winds occur is called the core.

It is impossible to make such predictions.

From 1950-2012, for which official records are available, Texas experienced 8,117 recorded tornadoes. The overall number is likely higher, as prior to the 1990s many of the minor tornadoes were missed.

As of February 13, 2015 the last recorded EF5 tornado struck Moore, Oklahoma on May 20, 2013.

During a tornado, vegetation and buildings ay be badly damaged to destroyed. There usually is not damage to the ground itself except in the most violent of tornadoes. In these rare cases, though, significant amounts of soil may be scoured away. When cities get hit, even relatively minor tornadoes can damage homes and knock out power. When violent tornadoes hit, people are usually killed and injured. Homes and businesses are destroyed. Damage in cities can be catestrophic, with whole neighborhoods leveled. After a tornado strikes, there are often rescue efforts to find anyone who is trapped or injured and to recover any dead bodies. Even then, some of the injured may later die of their injuries. Debris and fallen trees must be cleared from roads to gain access to the worst-hit areas. Power is restored and damaged buildings are repaired whiled destroyed ones are rebuilt or replaced. Evidence of the tornado's passage may last for decades in areas where the trees have to grow back.

Offically, the largest tornado on record struck near El Reno, Oklahoma on May 31, 2013. Radar and later damage surveys showed the tornado to be 2.6 miles wide.

The tornado-like whirlwinds that often occur in deserts are called dust devils. They are not actually tornadoes. On rare occasions, true tornadoes do occur in deserts, associated with infrequent severe thunderstorms.

There is no real evidence that they can. The most violent tornadoes have been known to have been turn from their foundations, but foundations have noot been blown away. Some foundations have been damaged, however. In a few cases concrete slabs have been shattered, but this was likely due to impacts from large objects rather than the tornado's winds.

On average, Oklahoma gets 7 tornadoes in June.