Tropical Storms Flashcards
What conditions are required for the formation of tropical storms?
- between 5-20 degrees N or S of the equator
- 26C+ water
- 70m deep water
- Low pressure belts
- light wind sheer
Why can’t tropical storms form on the equator?
they require the coriolis force
What scale is used to measure the magnitude of tropical storms?
saffir-simpson scale
What is the saffir-simpson scale based on?
wind speed
what way do storms rotate in the northern hemisphere?
anti-clockwise
What hazards are associated with tropical storms?
- storm surges/coastal flooding
- high winds
- river flooding
- landslides
How have tropical storms changed due to climate change?
more strong tropical storms
Why has climate change caused more strong tropical storms?
Increased ocean temp and air temp
= more air rises
= more oceanic evaporation
How does climate change impact the speed of tropical storms?
- polar areas get warmer
- less difference in atmospheric pressure between the Poles and Tropics,
- reduces wind speed between them
- slows down storms.
Why are slower storms more problematic?
- more rainfall in a given area
- greater wind damage
- larger wall of seawater (increased storm surge risk)
How many mm of rain fell in North Carolina in Hurricane Florence 2018?
760mm over 5 days
What impacts peoples’ vulnerability to tropical storms?
- storm intensity
- speed of storm movement
- distance from sea
- physical geography of coast
- preparations made by communities
- warnings and response
Describe and explain the pressure in a tropical storm
The air pressure is low because warm oceans (26C+) warm the air above them, and warm air rises rapidly, producing low pressure. Air then rushes in to take its place, and in turn rises, creating the strong winds.
Why is accurate evacuation advice important?
- ensures those in danger are moved to safety
- no unnecessary evacuation (expensive)
- ‘false alarms could cause complacence in future
What is prediction like for cyclones?
difficult to predict as more erratic (only 12hrs or so)
LICs impacted cannot prepare/evacuate people
Give three features of Bangladesh’s Cyclone Preparedness Programme
- EWS to identify incoming storms
- constructing storm shelters (4000 built, 1400 more planned)
- Planting mangroves
- encouraging emergency packs
- awareness campaign/education
What data would suggest that Bangladesh’s cyclone Preparedness programme was successful?
fall in storm related deaths
1970- 300,000ppl killed by 1 storm
2019- Storm Bulbul, 2.1 million relocated to storm shelters, only 8 deaths
What are 2 examples of mitigation against tropical storms?
- FEMA factsheet with advice (insurance, waterproofing, securing etc.)
- increasing resilience of infrastructure
Can storms be prevented?
NO
In the past, how have people tried to stop tropical storms?
- giant fans
- cooling ocean with icebergs
- cloud seeding
- exploding storms with hydrogen bombs
How much is rainfall expected to increase within 100km of the eye of the storm?
20%
What do the IPCC predict about tropical storms in the future?
- unlikely for frequency to increase
- number of Cat 4 and 5, 10% increase with 1.5C; 20% increase with 4C)
- 2-11% increase in intensity by 2100
How much rain hit North Caronlina from Hurricane Florence? what cat was this storm? List any other impacts?
- 760mm (over 5 days)
- 55 deaths
- cat 1
Why might climate change not be a significant impact?
- technology may have been poor, so storms might not have actually increased (especially somewhere like the Philippines)
- natural variations in climate
How much has storm length increased by in the last 20 years? (in North America)
60%
