Hazards (Wildfires) Flashcards
Distribution of wildfires
Requires a combination of dry vegetation and lightning strikes. Semi-arid climates (Mediterranean & Savanna). USA, Australia, Canada, Southern Europe.
Three type of wildfires
- Ground fire: beneath the roots and surface peat
- Surface fire: leaf litter and low lying vegetation
- Crown fire: tree canopy
Human ignition sources
- Accidental (bonfires)
- Arson
Natural ignition sources
- Lightning without much rain
- Electrical storms
- Volcanic eruptions
How does vegetation type affect wildfires?
Thick vegetation allows fire to spread quickly. Flammable oils from certain plants cause plants to burn quicker.
How do fuel characteristics affect wildfires?
Fine, dry vegetation causes fire to spread quicker but thick, dense vegetation causes it to burn more intensely.
How does El Nino/La Nina affect wildfires?
El Nino (warmer phase): provides warmer, wetter weather to grow vegetation. La Nina (cold phase): provides colder, drier weather to dry out vegetation
How does climate change affect wildfires?
Temperature increases cause an increase in wildfires and wildfire season length.
How does topography affect wildfires?
Fire spreads faster on hills as heat rises.
Short term responses to wildfires
- Firefighting: water, chemicals or retardants
- Diverting flames from settlements: bulldozing areas of vegetation, beating flames
- Evacuation
- Spraying water onto roofs
Prevention to reduce risk during wildfires
Educating on home safety and fire safety
Preparedness to reduce risk during wildfires
Emergency plans e.g. warning systems for potential risk factors
Mitigation to reduce risk during wildfires
Controlled burning of flammable material and creating fire breaks
Adaption to reduce risk during wildfires
Using non-flammable, non-toxic materials when building. Urban planning (more gaps between buildings)
Prediction to reduce risk of wildfires
Computer simulations to predict fire behaviour
