SUPPRESS WILDFIRE Flashcards
What are the critical dimensions of a safe area, in relation to flame height?
The size of this ‘safe’ area is proportional to the size of the flames and the fire intensity. The rule is that you need to be able to retreat to somewhere that is, in distance from the flames, four times the flame height
Heavy smoke at a bushfire can be a serious threat to your wellbeing. What are the three (3) acceptable ways to minimise this hazard?
- Always carrying your smoke mask and goggles and using them where necessary
- Avoiding unnecessary exposure to heavy smoke
- If trapped in heavy smoke, seeking fresh air pockets close to the ground
As a possible witness to an accident and subsequent investigation, when possible, you should take notes to assist. Describe the types of information you should be recording.
- The nature of the event
- The location
- Details of events leading up to the accident
- Personnel involved, including any eye-witnesses
- Initial action taken
- Any subsequent action
In implementing a defensive strategy of asset protection, what must be done immediately after the fire front has passed?
After the fire front has passed, check all structures for fire. Continue to check structures − ignition and early fire is often not obvious. Look particularly underneath buildings, under eaves, in roof cavities and in any openings that may have been entered by embers.
Machines such as bulldozers, working in a direct attack role on forest fires, should have what support?
If machines are making a direct attack on the head or flank of the fire, they should be closely supported by tankers.
What does the term mineral earth mean, in relation to constructing control lines?
When used in the context of fire control refers to a non-flammable surface (either natural or prepared) which provides a break in understorey, litter and humus fuels and hence a barrier (of varied effectiveness depending, among other things, on its width and the intensity of the approaching fire) to fire travelling on or near the ground surface.
Under what circumstances are defensive strategies necessary?
- Extreme fire behaviour is occurring (for example, flame height greater than 4 − 5m)
- Limited firefighting resources are available
- The fire is remote and not able to be immediately attacked
Why should back burn lighting crews be kept as small as possible?
This avoids confusion and minimises the danger to lighters working in from the control line, particularly in forest fuels.
What is a major safety consideration in making a parallel attack on a bushfire?
Crews should always ‘take the black with them’ in parallel attack so that control line construction crews can retreat to burnt ground quickly in the event of a change in flank fire behaviour.
Who can authorise back burning?
All backburns must be authorised by the incident controller
List three (3) sudden changes in fire behaviour that may affect crew safety while conducting firefighting operations at bushfire incident.
- Increases its rate of spread
- Increases its intensity (flame height)
- Changes its direction of spread
How can you minimise the risk of injury from falling limbs and trees?
- Always wearing an approved hard-hat
- Being conscious of overhead hazards − inspect trees above your locality for evidence of broken limbs that may fall
- Being aware of trees in your vicinity with weakened butts or trunks because of the fire − such trees should be identified and felled
List three (3) causes of heat illness?
- Radiant heat from the fire
- Environmental heat (the heat of the air around us)
- Dehydration (excessive fluid loss through sweating without adequate fluid replacement)
List and briefly describe the three (3) main factors that affect the fire behaviour of a bushfire.
- Fuel – what type of vegetation is burning, different fuels will cause different intesity
- Topography - the lay of the land (for example, hills and gullies) and will have considerable
impact on the way a fire will travel - Weather - Weather has a strong effect on fire behaviour. Key weather factors which can influence the behaviour of fire include temperature, humidity, precipitation, wind, atmospheric stability and lightning
Before a backburn is lit, the OIC must be satisfied that five (5) conditions are met. What are these conditions?
- A satisfactory control line has been established from which to light the backburn
- Weather and fuel conditions mean the backburn will be controllable
- Adequate resources are present to light the backburn and prevent its escape
- Adequate communications are established to maintain an appropriate flow of information during the activity
- Sufficient time exists for the backburn to penetrate far enough so that the junction zone effect will not endanger the control line
What are the major advantages of making an indirect attack on a bushfire?
An indirect attack involves falling back some distance from the fire perimeter and backburning from a strong control line
* It is the only offensive strategy that is effective against large, intense fires
* Enables choice in locating control lines
* Allows use of defensible, existing barriers
* Allows greater time for control line construction
* Crews are not affected by heat and smoke (until backburning commences)
List three (3) hazards unique to the mop-up and patrol phases of a bushfire incident.
- Fire may have weakened tree trunks and branches so these may fall. Look up for overhead hazards, and look out for fire-weakened trees
- The fire may have burnt out fuel that supported rocks or logs on a slope, allowing these to roll downhill. Always look for upslope hazards in hilly terrain
- Snakes and spiders may be agitated and could pose a greater than normal risk to firefighters. Take care when moving or splitting open logs or stumps
In an initial attack at a bushfire, who establishes a Control Point and where?
On arrival at the fire, the IC must establish a Control Point. The CP must be set up in a location that is capable of accepting and staging the requested recourses, not in the path of the fire, nor creating a hazard to traffic or the public and must be able to maintain comms with COMCEN and RDC.
LACES is a safety check before fighting or lighting a fire, which must be continually re-evaluated as conditions change. Provide a brief explanation of each component of the LACES bushfire safety acronym.
L LOOKOUTS
* Competent firefighter/s?
* Safe vantage point?
* Map and good communications?
* Everybody ‘looks out’ for the safety of everybody on the fire ground
A AWARENESS
* Terrain, weather, fire behaviour?
* Do you understand your assignment?
* Do you know what other crews are doing?
* Is everybody aware of the fire’s current and anticipated behaviour and of other fire ground hazards?
C COMMUNICATION
* Map and radio, reliable contact?
* Everybody speaks up and everybody listens, about what is happening and their concerns at the fire.
E ESCAPE ROUTES
* Suitable? Checked?
* Known to everyone?
* Everybody has an agreed ‘out’ plan, just in case things turn bad.
S SAFETY ZONES
* Suitable?
* Big enough? Close enough? Free of hazards?
* Everybody helps everybody else to survive; everybody supports the
List four (4) precautions that you (or residents) can take before the fire front arrives, to help avoid ignition of structures?
- Ensure all doors and windows are closed and secured
- Block down pipes and fill gutters with water if possible
- Remove doormats, move outdoor furniture off timber decks and away from the building
- Wet down structures and surroundings (preferably with foam)
Backburning is a strategy used throughout Western Australia in fire suppression. It can be dangerous if carried out under the wrong conditions. List two (2) disadvantages of using a back burn?
- The backburn may escape and create a new fire front ahead of the main Fire
- If the wind changes, a backburn may become an active front and threaten the proposed control line at another location where a backburn may not yet be established
- Erratic fire behaviour may occur at the junction zone between the spreading edge of the bushfire and the backburn, leading to spotting across the control line if the junction zone is not a sufficient distance in from the control line
How far should you keep from a bulldozer working in the forest?
When bulldozers are pushing over trees, keep two tree lengths clear (due to the ‘domino’ effect of one tree knocking down another)
Describe the Dead Man Zone and its potential consequences.
The Dead Man Zone is an area near the fire edge which could be consumed by a moving fire within five minutes
Why is direct attack on grass fires most often effective from the burnt side of the fire edge?
- Is easier to manoeuvre on the burnt ground (obstacles are more obvious)
- Is safer in the event of a sudden change in fire behaviour − because fuel has been consumed
- Allows better application of water to the base of burning material
