Wildfires Revision Help

Distribution of Wildfires Areas where it is hot and dry.A belt across the Sahel in Africa California( eastern USA)Parts of Australia

Causes of WildfiresNatural causes

• Lightning• Spontaneous heating ( material is

heated to a point that a spark is not needed)due to large amounts of plant build up.

• Volcanic eruptions• Spread quickly in hot dry weather ,

fallen branches and leaves dry and catch fire easily especially when there are strong winds e.g. Santa Ana winds (140 km per hour).

• South facing slopes -sun dries out the vegetation increasing risk of fires

• Steep slopes means fires spread quickly

Human Causes• Accidents children playing

with matches, camp fires cigarettes

• Broken bottles act as magnifying glass

• Slash and burn• Arson • Sparks from train wheels ,

machinery military training• barbeques

Causes of wildfires in New South Wales Australia

• Arson 37%• Farming 10%• Campfires 13%• Lightning 23%• Other 16%• Trains 1%

Effects of Californian WildfiresPrimary effects

• 9 people killed • 85 injured• 640,000 people had to

evacuate • 1,800 homes

destroyed($1.6billion damage)

• 200,000 hectares of grassland destroyed

• Water air pollution( 3 times normal level)

• Breathing problems for people

Secondary effects

• Loss of jobs and income for farm workers

• Loss of habitats for animals to survive

• Loss of income from businesses

Reducing the effects of wildfires

• Prevention educate people ( Smokey Bear campaign), how to reduce the risks of sparkes from vehicles, and how to dispose of cigarettes.

• Making homes as fire proof as possible .• GIS to forecast • Fire lines to prevent breaks

Responses to wildfires

• Fire fighters put out fires with water and gel• Fire resistant chemicals are released from aircrafts onto

wildlife • Areas ahead of fires are sprayed to stop it spreading• Helicopters are fitted with large buckets filled up with water

from lakes or the sea • Fire lines are created, without a supply of fuel the wildfire will

eventually burn out• Backfires is set alight to remove the fuel in the direction the

fire is spreading

Will there be more wildfires in the future

yes• Due to global warming

oceans have increased by 0.5C

• Last 30 years more tropical storms with wind speeds of 200km/hr

• Number of tropical storms has increases in last 100 years

no• We do not have evidence to

support this

• Satellite technology has only been used since 1960.

• There appears to be a natural cycle of variations in the number of hurricanes.

• 1995-2005 average wind speeds of storms increased by 15% and the length increased by 60%

• More tropical storms reaching category 4 and 5

Cost of damage is increasing

• More people are affluent ( well off) and choose to live or spend their holidays near the coast ..... The value of property has increased....... There is more infrastructure ( due to the increase in population)..... This has meant there is greater potential damage and the economic costs of hurricanes are increasing

More wildfires to come?

yes By 2007 the length of wildfire

season in USA had increased by 78 days

• Average size of wildfires and total area destroyed has increased

• Global warming • Increased temperatures

no• Part of a natural cycle

Cost of damage is increasing

• Cost of the damage of wildfires is increasing (MEDC).

• In USA over 10 million homes have been built in wildland-urban interface. More people are more affluent and choose to live or have a second home in remote rural areas