Tornadoes

Question 1

what is a tornado?

Answer 1

• a voilent, destructive weather system, with powerful rotating winds of up to 300km/h
• intense low pressure systems

Question 2

How do tornadoes develop?

Answer 2

•most destructive and deadly tornadoes develop from super cells, which are rotating thunderstorms with a well defined low-pressure system called a mesocyclone

• form when fast moving winds roll air below into a horizontal vortex above opposing surface winds.
• then buoyant air (warmed by the sun) near the ground level behind to lift a section of the horizontal vortex into a vertical position
• winds tilt the mesocyclone, allowing the storm to keep growing as warm air is sucked into the storm away for the cool downdraft (SUPERCELL)
• the supercell churns high in the air and in about 30% of cases leads to a tornado. this happens when air from supercell causes rotation near ground.
• not all thunderstorms create tornadoes.

Question 3

On avg. how many tornadoes hit the US every year and how many people do they kill a year? Why?

Answer 3

•about 1000 tornadoes hit the USA each year. on avg. tornadoes kill about 60 people each year- mostly resulting from flying debris

Question 4

What are the 3 damaging factors of a tornado?

Answer 4

1. winds are often so strong that objects in the tornados path are simply removed or severely damaged
2. strong rotational movement tends to twist objects from their fixings, and powerful uplift can carry some debris upwards into the cloud.
3. the very low atmospheric pressure near the vortex centre is a major source of damage. when a tornado approaches a building, external pressure is rapidly reduced, and unless there is a nearly simultaneous and equivalent decrease in internal pressure, the building may explode in the process of equalising the pressures

Question 5

Can tornadoes be predicted?

Answer 5

• no. at best they can be alert to the potential of a tornado by looking out for tornado conductive conditions such as warm air and fast moving winds above ground level
• storm spotters have been trained to recognise tornado conditions and report what they sea to the national weather service

Question 6

How can you prepare for a tornado?

Answer 6

• advice for FEMA is available on their website for organisations such as schools and nursing homes, who must identify a place of refuge for use in tornadoes.
• apps exist that allow tornado warning to be received by mobile phones
• prediction is more important than monitoring as most events are very short and unpredictable