First we need to figure out what we mean by "mini tornado", as the term has no definition.
Some European and Australian news outlets refer to the tornadoes they get as "mini tornadoes" regardless of how large or strong they are. These form in the same manner as any tornado.
Some people might use the term "mini tornado" to refer to any tornado that is comparatively small and weak. These form in the same way strong tornadoes do, but with less ideal conditions. Weak tornadoes and waterspouts can form in a couple other ways as well.
Finally, sometimes small whirlwinds such as dust devils are sometimes called "mini tornadoes." These are not actual tornadoes and have their own ways of forming.
As to formation:
The classic means of tornado formation is through a kind of thunderstorm called a supercell. Supercells typically form along a cold front or dry line, at the edge of or just inside a warm, humid air mass. The storms are fueled by the warm, moist air and rotate due to interactions with a condition called wind shear, where wind speed and direction changes with altitude. The area of rotation in these storms is called a mesocyclone. Under the right conditions a downdraft can wrap around the mesocyclone, tightening and intensifying it into a tornado. Mesocyclones can sometimes be embedded in a squall line as well.
Sometimes "spin up" tornadoes can form along the turbulent leading edge of a severe squall line. These tornadoes are generally short-lived and weak. There is yet another kind of tornado called a landspout. These form when there is a broad circulation of air at ground level that gets caught in the updraft of a developing thunderstorm, which stretches and tightens it into an intense vortex. Waterspouts form in a similar way.
Finally we have other whirlwinds that are not considered tornadoes, but look a bit like them. Dust devils are the most common example. These form on days when the sun heats a patch of ground, creating a layer of extra hot air right at ground level. This will rise up in a thermal. Sometimes this updraft will catch an eddy in the wind, causing it to tighten and intensify, lifting dust and sand into the air. People have also observed things such as "haydevils" which are essentially the same thing. Finally there are the whirls that pop up on windy days. These are simply eddies that form from the wind going around things such as buildings and trees. They sometimes can be seen when they pick up snow, leaves, or other light materials.
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.
Tornadoes are often referred to simply as "tornadoes" or "twisters."
No, a dust devil is not a mini tornado. Dust devils are small, rapidly rotating columns of air that form under sunny conditions, while tornadoes are large, violent rotating columns of air that form during severe thunderstorms. Dust devils are typically harmless and short-lived compared to tornadoes.
The plural of tornado is tornadoes.
Tennessee averages about 30 tornadoes per year.
The term "mini tornado" does not have an exact definition. It has been applied to a number of different phenomena. Some people have called small whirlwinds such as dust devils mini tornadoes. Such whirlwinds are not actual tornadoes but may superficially resemble them. News outlets in Australia and Europe may sometimes refer to the tornadoes they get as "mini tornadoes," even in instances of large, significant tornadoes. They equivocate like this because they are reluctant to admit that tornadoes occur in those areas. People may occasionally call small, weak tornadoes mini tornadoes.
That depends on what you mean by "mini tornado" as it has no real definition. If you mean small, weak tornadoes, then yes. Even in areas prone to large tornadoes, the smaller ones will still be in the majority. However, weak tornadoes are rarely heavily covered unless they strike in places not not normally associated with tornadoes.
Keep on eating up mini tornadoes
Generally, small tornadoes do less damage than large ones, but some small tornadoes have been very destructive.
Keep on eating up mini tornadoes (im not sure if there even is an f6)
That depends on what you mean by "mini tornado," as there is no real definition for the term. Some people apply the term to whirlwinds such as dust devils, which aren't really tornadoes. In that case, then no. Sometimes, especially outside of the U.S. tornadoes with relatively narrow damage paths are referred to as "mini tornadoes," regardless of intensity. In that case, such a tornado may be able to lift up a cow depending on how intense it is. One tornado in France in 2008, which some outlets called a "mini tornado" caused isolated F4 damage. Such a tornado could pick up cows and much larger objects.
No. While the Chesapeake Bay areas does get tornadoes, it is not particularly tornado prone.
It depends on the tornado. For most tornadoes the fastest winds occur at the edge of the core. For other tornadoes, especially large and/or strong ones the strongest winds occur in the suction vorticies, which are like mini tornadoes moving within the main circulation of a tornado. Tornadoes with this feature are called multiple vortex or multivortex tornadoes.
Tornadoes in the U.S. are called tornadoes.
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.
It depends on what you mean by extreme. Tornadoes of EF4 and EF5 tornadoes, however are often referred to as violent tornadoes. These account for about 1% of all tornadoes.
Tornadoes don't get named, Hurricanes do, but Tornadoes don't.