Tornadoes are one of the most extreme weather phenomena and can be very destructive.
The United States sees the most tornadoes of any other country, on average 1,200 a year. An average of 60 people per year die from tornadoes.
In Colorado, an average of 47 tornadoes occur per year.
Types of tornadoes
Supercell tornadoes are the classic tornado you think about, which can become very destructive. These tornadoes form from a supercell thunderstorm. These are powerful thunderstorms, with a rotating updraft.
Non-supercell tornadoes are landspouts, waterspouts, and gustnadoes. These do not form from rotating thunderstorms.
Enhanced Fujita Scale
The current method of determining top wind gusts of a tornado is from surveying storm damage. The enhanced fujita scale categorizes the extent of damage to specific tree types and building types.
Tornado formation
Tornadoes are hard to predict because they are rare and small scale. It is also difficult to place weather instruments in the direct path to gather data. The ability to predict whether an environment can spawn tornado producing thunderstorms has greatly improved, but determining which if any of those storms will produce a tornado is still a difficult task.
In a thunderstorm environment, there needs to be wind shear. Wind shear is wind that changes in direction and/or speed. Wind shear can sometimes create horizontal spin in the atmosphere. That spin will be turned vertically by a strong thunderstorm updraft, creating a rotating thunderstorm, or supercell.
For a tornado to form, the wind shear needs to be particularly strong. A strong theory suggests that an intense change in air density is also needed to trigger tornado formation. This can be found at the boundary of rain cooled, sinking air and warm, humid and buoyant air in the storm environment.
Experiment
Time: 5 minutes
Materials:
- 2 plastic water bottles
- food coloring
- Tornado Tube (found on Amazon or some craft stores)
- (optional) Glitter or lightweight beads
Instructions:
- Fill one bottle with water to the top
- add food coloring and optional glitter/beads to water
- connect with Tornado Tube
- flip bottles so water is on top
- shake the bottles unti the water starts flowing
