It you want to get very technical, they occur in the U.S. and Canada, as these are the only two countries that use the Enhanced Fujita scale. However, if you consider tornadoes of equivalent intensity (F3 on the Fujita scale, T6 and T7 on the TORRO scale), they can occur in most areas that have a temperate to tropical climate that is not arid. In the U.S. all but six of the states have had at least one F3 or EF3 tornado since 1950. Many countries have tornadoes that go unrated that are almost certainly of EF3 intensity, if not higher. The majority of EF3 and stronger tornadoes occur in the U.S.
About 96% of tornadoes are given ratings lower than EF3.
They fare pretty well against weak tornadoes, but still can suffer heavy damage from intense (EF3 and stronger) tornadoes.
mostly an EF5 tornado and sometimes EF3 or EF4 tornadoes
Most tornadoes can't but one EF3 or stronger can.
EF3 tornadoes have been known to toss train cars, though usually no more than a few yards.
No. Intense tornadoes (those rated EF3 or higher) only account for about 3% of tornadoes in the U.S. Most tornadoes are rated as weak, EF0 or EF1.
Yes. Zim's ship is very small. EF3 tornadoes have been known to pick up light train cars.
Yes, they can. It usually takes at least an EF3 tornado to do so, though.
In the years 1950-2011 Kansas had 161 confirmed F3 and EF3 tornadoes. Records prior to 1950 are incomplete.
Tornadoes are sometimes divided into "weak" tornadoes "strong" and "violent" tornadoes. Weak tornadoes are those rated EF0 and EF1. Most tornadoes are weak. Strong tornadoes are those rated EF2 and EF3. Violent tornadoes are those rated EF4 and EF5. They are the rarest of tornadoes, only about 1% of tornadoes are this strong.
The strongest tornadoes occur the least often. Only a few percent of tornadoes are rated EF3 or higher. Less than 1 in a thousand receive an EF5 rating.
Arizona does get strong tornadoes, but very rarely. Since official record keeping began in 1950, 3 tornadoes in Arizona have been rated F3 or EF3, with nothing rated higher.