Tornadoes come from mainly two types of thunderstorms: supercell and non-supercell.
Tornadoes that come from a supercell thunderstorm are the most common, and often the most dangerous. A rotating updraft is key to the development of a supercell, and eventually a tornado. There are several ideas about how the rotation process starts. One way a column of air can start to rotate is from wind shear.
Wind shear is when winds at two different levels above the ground blow at different speeds or in different directions. An example of wind shear that can eventually produce a tornado is when winds at ground level, often slowed down by friction with the earth’s surface, come from the southwest at 5 miles per hour (mph).
Higher up is a different story, at 5000 feet above the same location, the winds are blowing from the southeast at 25 mph. An invisible cylinder of air starts to rotate horizontally. Rising air within the thunderstorm tilts the rotating air from horizontal to vertical- the area of rotation now extends through much of the storm.
Once the updraft is rotating and being “fed” by warm, moist air flowing in at ground level, a tornado can form. Experts have many ideas about this as well!
Not all tornadoes come from supercells, what about tornadogenesis in non-supercell thunderstorms?
FYI: tornadogenesis is the process by which a tornado forms.
Almost 20% of all tornadoes that are associated with lines of strong thunderstorms are called “quasi-linear convective systems” (QLCS). QLCS tornadoes tend to occur during late night and early morning hours. These tornadoes tend to be weaker and shorter-lived on average compared to those associated with supercell thunderstorms.
Another type of non-supercell tornado is a landspout. A landspout is a tornado with a narrow, rope-like condensation funnel that forms while the thunderstorm cloud is still growing and there is no rotating updraft – the spinning motion originates near the ground. Waterspouts are similar to landspouts, however, they occur over water. Damage from Waterspouts tends to be EF2 or less.
Tornadoes can be visually identified in a number of different ways:
Rope tornadoes are some of the smallest and most common types of tornadoes. They get their name from their rope-like appearance. Most tornados start and end their life cycle as a rope tornado before developing into a larger tornado or dissipate.
Despite their size, rope tornadoes can still be dangerous to those in their path.
Cone tornadoes get their name from their shape, similar to rope tornadoes. A cone tornado is narrower where they touch the ground than where it meets the base of the thunderstorm. This particular type of tornado is generally more dangerous than rope tornadoes.
A stovepipe tornado is similar to a cone tornado. The main difference is that a stovepipe has the same width at the base of the thunderstorm and where it touches the ground.
A wedge tornado appears wider than tall and can leave a large trail of destruction behind it. Wedge tornadoes are typically defined as major tornadoes, meaning that they are usually rated EF-3 or higher.
Some of the largest and most destructive tornadoes in history fall under the wedge tornado type.
Multi-vortex and satellite tornadoes
Thunderstorms can produce multiple tornadoes throughout their life cycle, however, some can produce multiple tornadoes a the same time…
PLEASE REMEMBER: REGARDLESS OF THE TYPE, EACH AND EVERY TORNADO CAN BE DANGEROUS.