Tropical storms
A violent rotating storm
Reason for mid latitude location
- Warm climate necessary for hot surface water of 27C to provide energy
- Low wind shear preventing hot air to dissipate
Sandy timeline
- October 2012
- Low wind shear and water above average temp for the year
- Eye moved north - diameter of 1100 miles
- Course shifted 8 days before landfall, moving left towards US, due to cold air and low pressure in Greenland, eastward jet stream
- Pushed storm to warmer coastal waters combined with full moon, increasing potential storm surge
Sandy social effects 7
- 111 deaths
- 24 states effected
- 75% NY isolated with no power
- 4% had to be rehoused
- looting
- queues for fuel
- 3% still homeless after a year
Sandy political effects
- Occurred weeks before 2012 election
- Increased pressure to address climate change
Sandy economic effects
- $63 billion in damages
- Energy Grid damaged
- NYSE closed
- Loss of economic activity
- Loss of water supply and phone lines
Sandy environmental effects 4
- Poor air quality
- Water pollution
- Trees uprooted
- Sewage leaks / overflow
Sandy short term responses 6
- 1 million forced to evacuate
- 17.5 million meals given by Red Cross
- 7 million kits of medical supplies
- 11000 sheltered
- National guard deployed
- Course of the hurricane confused efforts
Sandy long term responses
- 23000 people and businesses given assistance
- $10 billion to respond with $50 billion to rebuild
- Accusations of misallocation of Red Cross supplies pulling PR stunts
Hurricane prediction
- Only occur at certain times of year
- Tracking by air = limited scale / prediction
- Satellites = birds eye view, determine path, track storm
- Supercomputer = can predict paths and guide response, needs constant data
Hurricane scale of magnitude
Saffir-Simpson scale 1 to 5 based on wind speed
Why is monitoring hurricanes beneficial
People can evacuate sooner reducing potential deaths, and those at risk understand potential of storm and can prepare
Why use Saffire-Simpson scale
Easy to compare magnitude of events and categorise as well as compare outcomes
Tropical storm hazards 5
- Strong winds
- Heavy rainfall
- Storm surges
- River flooding
- Landslides
Storm surge
- Rise in sea level that occurs during tropical storms with strong winds pushing water to shore
- Form when low pressure at centre of storm lifts the water up (rises by 1cm for every millibar of pressure)
Strong Winds
- Form when air rises and cools causing it to condense and form clouds
- Difference in gradient between centre and higher pressures not far away causes air to rush away to lo pressure
Wildfire
Any rural fire which is uncontrolled and spreading
Factors for wildfires occurring
- Fuel = Oil spills, fossil fuels, dry vegetation
- Oxygen
- Heat = Sunlight, BBQ, lightning, fireworks
- Wind accelerates spread
El Nino phenomenon
A time of abnormal weather that occurs approximately every 2-7 years.
Warm water shifts to the east, leading to abnormally drier and warmer temperatures with plants drier
Why was Australia susceptible to wildfires in 2019/20
- El Nino
- Warmer temperatures lead to dryer conditions, reduced humidity and dried plants
- Rural land largely flat shrubs for fires to spread with fences to fuel
Wildfire behaviour
- Radiation = heat causing combustion
- Connection = similar to radiation but upwards
- Conduction = Occurs when flames are in direct contact with another fuel
What affects wildfire behaviour
- Weather = most influential, no control, can change rapidly, wind can carry embers
- Topography = slope of area affects speed of spread, faster uphill
- Fuel = Most preventable significant factor in long term existence
Ladder fuels
Combustible materials that aid the spread of fire from the surface to the upper canopy, making fire harder to fight and easy for embers to fly
Causes of wildfires
99% due to human activity - lightning exception
