Yes. Some twisters have touched down and joined together to create a big tornado.
edit: when tornadoes form like that its called a multivotex tornadoTornadoes can merge together, yes, and vortex physics predict that the combined tornado will be larger than either of the merging tornadoes. However, most tornado mergers involve a large tornado absorbing a small one, so the larger tornado is not affected very much.
No large tornadoes have struck Baltimore since official records began in 1950. Several weak tornadoes and one significant (F2) tornado have hit the city. No tornadoes have struck Baltimore in 2015 as of June 11.
When two tornadoes combine, it is known as a tornado outbreak. The resulting tornado can become larger, stronger, and more destructive as it merges with the energy and circulation of the other tornado. The combined tornado can create a wider path of destruction and pose an increased threat to affected areas.
An infamous tornado is one that is know for being particularly devastating. A number of tornadoes have become infamous, including the Tri-State tornado of 1925, the Wichita Falls tornado of 1979, and the Oklahoma City tornado of 1999.
It appears to have been one tornado.
Tornadoes can merge, but it is rare. Most often it occurs when one large tornado absorbs a smaller one.
No. A cyclone can produce tornadoes, but it cannot become one. They are two very different types of weather event.
Most likely not, as the chances of having two tornadoes close enough to merge is unlikely. However, some tornadoes, especially large, violent ones, somtimes have a series of smaller vortices inside the main vortex of the tornado. Under the right conditions these vortices can become visible, resulting in a tornado with multiple funnels. Tornadoes with four or more funnels have been observed. In some instances, these vortices will be visible for a time and then suddenly become hidden within the main funnel or debris cloud, making it look like they have merged.
Oklahoma City has been hit by many tornadoes. The most famous Oklahoma City tornado was the one which struck on May 3, 1999. That tornado was a mile wide and was rated F5.
It is rare for tornado to actually merge, and when it does happen it usually involves a large tornado absorbing a smaller one. In the rare cases that tornadoes do merge they simply form one bigger tornado.
When two tornadoes collide, it is most likely that the stronger tornado will absorb the weaker one. The collision may lead to an increase in size and intensity of the tornado before eventually dissipating.
A tornado anywhere is a violent event. If you mean by the technical definition of a violent tornado, one rated EF4 or EF5, such tornadoes do occur fairly regularly in Tornado Alley, but make up a very small minority of the tornadoes that occur there. As with most places, most of the tornadoes in Tornado Alley are rated EF0 or EF1.