Wildfire Hazards - 3.1.5.6 Flashcards
Wildfire
Uncontrolled fires that burn grass, shrubs, trees and other vegetation.
Surface fires
Fires burn along the forest floor burning leaf litter and fallen branches. They are easy to control.
Ground fires
Fires which burn organic matter in the soil, such as peat can last a long time.
Crown fires
Fires burn the top layer of foliage known as the canopy. They are very hot and hard to control.
Semi-arid
Regions of the world which are very dry and experience drought regularly (i.e. Australia).
Dry Season
A time of the year when little rain falls and wildfires are common.
Arson
When fires are started deliberately.
Heatwave
A period of extreme heat whereby vegetation becomes dry and combustible.
Humidity
The amount of moisture in the atmosphere. If it falls below 7% the risk of wildfires increases.
Firebrands
Burning fragments of vegetation are carried ahead of the fire by convection currents and strong winds.
El Nino
A climatic event (which occurs every 6-8 years) whereby sea temperatures shift across the Pacific Ocean resulting in drought conditions (and increased wildfire risk) in Australia and Indonesia.
Topography
The shape of the land (relief) impacts the speed and direction of the wildfire. Wildfires travel 400% faster upslope due to preheated vegetation.
Mitigation
To reduce the severity of an event and lessen its impact. This can be done pre- and post-hazard.
Prevention
Actions aimed at stopping wildfires from starting.
Adaption
Accepting wildfires is inevitable and adapt behaviour accordingly.
Preparedness
Increasing people’s awareness through actions that minimise the likely impact of hazards (and reduce their vulnerability)
Red Flag warnings
The US Weather Service issues warnings to alert the public and fire departments that conditions are ideal for wildfire and its rapid spread.
Direct attack
Any strategy which is applied directly to the burning fuel i.e. firefighters, fire beaters, air drops of water and retardant chemicals.
Indirect attack
Any strategy which is prepared far away from the fire’s edge in preparation for its advance i.e. Spraying ahead, creating firebreaks and back burning.
Stay or go policy
A much-criticised piece of governmental advice recommends ‘Leaving early is still the safest option, but staying to defend a well-prepared defendable home is also a sound choice’.
Indian Ocean Dipole
An alternating pattern of ocean temperatures found to the west and north of Australia - which can lead to dry conditions favourable for a wildfire.
Post-traumatic stress disorder.
An anxiety disorder caused by very frightening or distressing events. People relive the event through nightmares and flashbacks and may experience feelings of isolation, irritability and guilt for a long time.
Spot Fire
A new fire which ignites outside of the original fire perimeter.
Light Fuel
Small material which can catch fire easily but only for a short amount of time (i.e. leaves, pine needles, grass)
Heavy Fuel
Large material which once on fire burns for a long time (i.e. trees)
