This question can be interpreted multiple ways.
In terms of how wide a tornado is (diameter), the average tornado is 50 yards (45 meters) wide,. But sizes can range from less than 10 yards (9 meters) to as much as 2.5 miles (4 km).
In terms of path length (how far a tornado travels), the average damage path is 5 miles (8 km) long, but it can vary from only a few yards (meters) to over 200 miles (320 km).
In terms of duration (how long a tornado lasts), the average tornado is on the ground for about 10 minutes. But a tornado can last anywhere from just a few seconds to over 3 hours.
In terms of how high up a tornado extends (how tall it is), they can range anywhere from 1 to 4 miles (1.6 to 6.5 km).
That would be a tornado. Once the process starts, a tornado can form in a matter of seconds. Hurricanes, by contrast, usually take several days to form and are easy to track.
A tornado watch is issued by the National Weather Service when weather conditions are favorable for tornadoes to develop. It means you should stay informed and be prepared to take action if a tornado warning is issued for your area. It is a warning for potential tornado development, not a guarantee that a tornado will occur.
The National Weather Service issues a tornado warning when a tornado has been spotted on the ground or indicated by weather radar in your area. This is to alert residents to take immediate shelter and protect themselves from the approaching tornado.
A tornado would occur in the troposphere, which is the lowest layer of the atmosphere where most weather phenomena, including storms, take place.
A violent whirling wind associated with thunderstorms is known as a tornado. Tornadoes can cause significant destruction and are often accompanied by severe weather conditions such as thunderstorms, lightning, and heavy rainfall. It is important to take precautionary measures and seek shelter when tornado warnings are issued.
About 40 minutes direct or 1hr 20min if they touch-down at Plymouth
It could take months and even years
Only to a very limited degree. Scientists can determine when conditions are favorable for tornadoes to develop (in which case a tornado watch is issued), or even if a tornado may be developing (which would prompt a tornado warning), but cannot predict exactly where or when a tornado will touch down.
about 2 decades
As of December 21, 2012 there are no known tornadoes currently on the ground. However it is difficult to type an answer on "current tornadoes" as most tornadoes last just a few minutes and some last only a few seconds. On top of that, it can take a while to confirm that a tornado actually did touch down.
That depends on how far away the next destination is and how fast the tornado is traveling.
1-2 years
About 1 hour 50 mins in the air, from take-off to touch-down.
Once formation starts, a tornado usually takes just a few minutes to a few seconds to touch down. A typical tornado will be into and out of a given spot after just a few seconds. A large or slow moving tornado may take a minute or more.
Very little time at all. The average tornado is about 50 meters wide, and a tornado can reach such a size in a matter of seconds.
Take cover under a desk or in the hallway facing a wall. Crouch down and cover your head. As always when there is a tornado, stay away from windows
About as long as a computer, maybe an hour.