Tornado intensity is determined by damage, which is used to estimate wind speed. These wind speed estimates are used to sort a tornado into one of six categories from EF0 to EF5.
A tornado typically loses strength when cold or dry air undercuts the thunderstorm updraft that drives it. This cuts off the supply of air that power the storm and, in turn, the tornado.
No, it is possible to measure the strength of a tornado, though direct measurements are rare. Most tornadoes have their strength estimated based on the severity of the damage they cause....