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).
In most cases it takes about 30-45 minutes for a tornado to form from when a thunderstorm starts rotating. Once the tornado itself starts forming though, it can touch down in a matter of seconds.
From when a thunderstorm first starts rotating it can take 30-45 minutes to produce a tornado, though some can become tornadic in as little as 15. Once a tornado starts to form it can touch down in under a minute.
It varies considerably depending on how large the tornado is and how fast it is moving. A typical tornado will not be over any given spot for more than a few seconds, but it can take much longer. A half-mile wide tornado moving at the typical speed of 30 miles per hour would take a full minute to clear a location. One tornado was reported to have stood still over the same spot for more than 90 minutes.
It typically takes 30-45 minutes between when a thunderstorm first starts roatating and when it produces a tornado. Once a tornado starts to develop in can touch down withing a few seconds.
There is no certain temperature for tornadoes to form, though often the weather is hot and humid before a tornado.
spring and summer
4 days
The thing is, it can't. Maybe billions of tornados could, but I highly doubt that will ever happen.
It can take several hours for the waves to calm down after the first wave hits.
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.
About an hour.
The safest place to take cover from a tornado, even if you do have a bathtub, is your basement. If you have neither find a room in the center part of you house away from windows.
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.
2-5 minutes
About 40 minutes direct or 1hr 20min if they touch-down at Plymouth
It could take months and even years
Yes, though it would take a very strong tornado to do so.
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.
six years
about 2 decades
If the tornado is close, leave the vehicle and take cover in a nearby sturdy building. If none is available, lie down in a ditch.
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.