Tornados

What are they?Where do they form?

Why are they hazardous?What impact do they have on people and property?

How do humans respond to the tornado hazard?

What is a tornado?

• A localized and violently destructive column of air descending from a cumulonimbus cloud and in contact with the ground

• Not always visible but usually a condensation funnel develops giving the characteristic tornado formation

• Can be anything from 100m to 1.6km in diameter

• Tornados can be on the ground 100km or more in extreme cases

Global Distribution

Where do they form - USA?

A Little More Detail

But Why?

Its all due to different air masses.

And How?

A sequence of images showing the birth of a tornado. First, the rotating cloud base lowers. This lowering becomes a funnel, which continues descending while winds build near the surface, kicking up dust and other debris. Finally, the visible funnel extends to the ground, and the tornado begins causing major damage. This tornado, near Dimmitt, Texas, was one of the best-observed violent tornadoes in history

Inside – What is it like?

Go to this website for a cool animation

Measuring the IntensityThe Enhanced Fujita Scale

Don’t Forget

• You need case studies to highlight the impact on people and property.

• You need to understand and explain the human response.

• Tornados are hazardous because of their sporadic unpredictable nature - although the Storm Prediction Centre, Norman Oklahoma does issue risk category warnings -

And then there is the storm chasers!