Weather hazard case studies

Case studies of two contrasting natural weather hazard events arising from extreme weather conditions. The case studies must include a natural weather hazard from each bullet point below:

  • flash flooding or tropical storms
  • heat wave or drought.

There must be one UK based and one non-UK based natural weather hazard event.

Flash flooding – Boscastle, UK

Key facts

16th August 2004

Village built at the confluence of the River Jordan and the River Valency


Causes Natural

  • Torrential rain: over 500mm rain fell in 4 hours, remnants of Hurricane Alex. Weather system remained stationary over area due to converging winds.
  • Small catchment area (about 23km2)
  • Impermeable upland area (Bodmin Moor)
  • Steep-sided valleys

Extremely wet summer, by August ground was saturated. Human

  • Building along river
  • Construction of small bridges across river (trapped material behind them creating small dams)
  • River narrowed through Boscastle reducing capacity

Deforestation in valleys Consequences Social

  • Destroyed homes
  • Stress and anxiety for local people

Cars belonging to more than 1,000 people washed away Economic

  • 25 business properties destroyed
  • Bridges and roads damaged
  • 4 footbridges washed away
  • Visitor centre destroyed
  • Area relies on tourism for 90% income, most of which earned in summer months. Floods dramatically affected earnings.
  • Insurance companies paid out an estimated £20 million to repair damaged property


  • Gardens and pavements destroyed by weight of floodwater

Responses Short-term Major incident declared at 5pm. RAF search and rescue were alerted to rescue trapped people. No-one died mainly due to the rapid response of the emergency services. Long-term

To reduce the risk of future floods, a £4.6 million flood defence scheme was completed in 2008.

  • Low bridges removed
  • River widened through Boscastle
  • New flood defence wall built in village centre
  • River bed lowered by an average of 0.75m
  • Trees near to river removed
  • Landowners encouraged to maintain vegetation cover on valley sides

Drought in Australia

Key facts

  • South-east Australa suffered from a severe, long-term drought from 2001/2-2009
  • It was the driest period in 125 years
  • Known as the Big Dry or the Millenium Drought
  • Worst hit area was the Murray-Darling Basin, an important agricultural region

Causes Natural

  • Naturally low rainfall due to global atmospheric circulation (the 30°S high pressure belt runs through Australia)
  • El Nino events in 2002-03, 2004-05, 2006-07
  • Scientists think that climate change may be increasing global temperatures and changing rainfall patterns. Temperatures in Australia were higher than normal during this period, resulting in more water being evaporated. Weather fronts that normally bring rain moved further south, away from Australia, causing annual rainfall to be lower than normal.


  • Country is overpopulated; it cannot maintain its current population growth in relation to access to water
  • Murray-Darling basin is home to 2 million peole and is under a lot of pressure to provide the water needed to support agricultural production in the region. 40% of Australia’s agricultural produce comes from this region and it contains 70% of irrigated cropland and pasture.

Consequences Social

  • People in rural areas left due to a lack of water, placing greater pressure on the population of cities
  • Rural suicide rates soared


  • Farmers had to sell cattle as they couldn’t afford to feed them
  • Food prices rose as Australia became more dependent on imports
  • Water bills rose 20% in 2008
  • Tourism decreased
  • Agricultural production decreased
  • 10,000 people directly employed by the cotton-growing industry were affected
  • Number of dairy farms more than halved
  • 100,000 people employed in farming lost their jobs


  • Water levels in lakes and rivers (especially Murray and Darling rivers) ran low
  • Loss of vegetation, wildlife and biodiversity
  • Soil erosion
  • Dust storms
  • Drought conditions perfect for wildfire, over 30,000 sqkm land burned destroying hundreds of houses and killing 8 people.
  • Grassland turned to scrubland
  • Energy from HEP was reduced leading to more pollution as Australia resorted to using fossil fuels
  • Water quality reduced as toxic algae outbreaks occurred in depleted rivers, dams and lakes

Responses Short-term

  • Water conservation measures introduced e.g. the 3 million people who rely on the Murray river for their water supply had their allocation reduced
    • Legisalation to ban car washing and limit showers to 4 minutes
    • Recycling waste water from showers, baths, washbasins and washing machines, known as greywater
  • Government provided over 23,000 families and 1500 small businesses with income support to help them survive
    • Farmers claimed $400-600 in assistance per fornight
    • Govenment paid out $1.7million per day in drought relief to farmers
  • Subsidised rainwater storage tanks for homes


  • Cities such as Sydney built desalination plants to turn sea water into drinking water
  • Investment in improving drought forecasts so farms can prepare better, improving irrigation schemes and developing drought-resistant crops