Geography A2 Notes
Notes
Hurricanes
What are Tropical Storms:
* Large rotating storms around a centre of very low pressure. * May be 800km across and 12km high * Wind speeds may reach 180km per hour. * High intensity, high volume rainfall (up to 500mm in 24hr)
There are also known as:
* Hurricanes (North Atlantic) * Cyclones (Indian Ocean and the Bay of Bengal) * Typhoons (Western Pacific) * Willy Willies (unique to Australia! Although often still called cyclones e.g. Cyclone Tracey)
The conditions required for Hurricanes to form: * Sea temperatures greater the 27’C for a significant period of time and over a depth of at least 50m) * Sufficient spin from the earth’s rotation (Coriolis effect) to trigger the vicious spin in the centre of the hurricane (5’-30’ north and south of the equator)
The cross section of a hurricane:
Hurricanes can be monitored easily through: * Satellite technology. * Advanced meteorological technology
Links
Animation of the formation of a Hurricane
Hurricane Sandy Case Study
Hurricane Katrina Case Study
Tornadoes
* Tornadoes are a complex phenomena and little understood, yet one of the most destructive. * The country with the greatest density per km square is the UK. * The highest number of deadly tornadoes is found in Tornado Alley, USA.
What is a tornado: * A vortex (whirling mass of air)descends from well developed cumulonimbus cloud. * A tornado vortex is in contact with the cloud and the ground * Violent winds (100m per second) * Extreme pressure gradients (25mb per 100m) and air rushing from the high to low causes the spinning winds. (Hurricanes 20mb per 100km!!) * Diameter of funnel is rarely more then 200m
Key conditions required for a tornado to form:
* Moisture * Warmth * Lift * Wind shear
Tornado Risk map USA
Tornado frequency map USA
Tornado Hazard Impacts
* Strong winds move/damage objects
Hurricanes
What are Tropical Storms:
* Large rotating storms around a centre of very low pressure. * May be 800km across and 12km high * Wind speeds may reach 180km per hour. * High intensity, high volume rainfall (up to 500mm in 24hr)
There are also known as:
* Hurricanes (North Atlantic) * Cyclones (Indian Ocean and the Bay of Bengal) * Typhoons (Western Pacific) * Willy Willies (unique to Australia! Although often still called cyclones e.g. Cyclone Tracey)
The conditions required for Hurricanes to form: * Sea temperatures greater the 27’C for a significant period of time and over a depth of at least 50m) * Sufficient spin from the earth’s rotation (Coriolis effect) to trigger the vicious spin in the centre of the hurricane (5’-30’ north and south of the equator)
The cross section of a hurricane:
Hurricanes can be monitored easily through: * Satellite technology. * Advanced meteorological technology
Links
Animation of the formation of a Hurricane
Hurricane Sandy Case Study
Hurricane Katrina Case Study
Tornadoes
* Tornadoes are a complex phenomena and little understood, yet one of the most destructive. * The country with the greatest density per km square is the UK. * The highest number of deadly tornadoes is found in Tornado Alley, USA.
What is a tornado: * A vortex (whirling mass of air)descends from well developed cumulonimbus cloud. * A tornado vortex is in contact with the cloud and the ground * Violent winds (100m per second) * Extreme pressure gradients (25mb per 100m) and air rushing from the high to low causes the spinning winds. (Hurricanes 20mb per 100km!!) * Diameter of funnel is rarely more then 200m
Key conditions required for a tornado to form:
* Moisture * Warmth * Lift * Wind shear
Tornado Risk map USA
Tornado frequency map USA
Tornado Hazard Impacts
* Strong winds move/damage objects