Suppress Wildfire Flashcards
(29 cards)
What are the critical dimensions of a safe area, in relation to flame height?
- Minimum safe distance from radiant heat is four times the flame height
Heavy smoke at a bushfire can be a serious threat to your wellbeing. What are the three acceptable ways to minimise this hazard?
- Work upwind wherever possible
- Wear appropriate PPC and upgrade when necessary
- Reduce working duration in smoke
- Take rest breaks in clean air
- Rotate positions to minimise prolonged exposure
- Ensure windows are up and cabin ventilation is recirculated when driving in smoky conditions
As a possible witness to an incident and subsequent investigation, when possible, you should take notes to assist. Describe two types of information you should be recording enroute to the incident, on arrival, during suppression and following extinguishment? (following the incident describe one type of information)
- Enroute: vehicles leaving the scene with hast, colour of smoke
- On arrival: possible witnesses information, gates opened/closed/locked/locks cut
- During suppression: unusual smoke/ flame colour, rate of spread for the head fire
- Following extinguishment: physical evidence i.e broken glass, fuel cans, matches
Machines such as bulldozers, working in a direct attack role on forest fires, should have what support?
- Tankers with a minimum of 500L (DBCA) or 1000L (DFES) of water for protection of the machine and operator
What does the term mineral earth mean, in relation to constructing control lines?
- This term refers to ground where all vegetation cover has been removed and only rocks and soil (minerals) are exposed.
Under what circumstances are defensive strategies necessary?
- When the fire is in a remote location
- Fire is too intense to be safely or effectively attacked or extinguished by an offensive strategy
- There are limited firefighting resources
Why should back burn lighting crews be kept as small as possible?
- To avoid confusion and minimise the danger to lighters working in from the control line
Who can authorise back burning?
- Backburning must be authorised by the IC
List three characteristics of a bushfire behaviour that may affect crew safety while conducting firefighting operations at a bushfire incident.
- Increased rate of spread
- Increased fire intensity (flame height)
- Changed direction of spread
How can you minimise the risk of injury from falling limbs and trees? Name five.
- Always maintain situational awareness
- Wear PPC/PPE, including helmet
- Check for hollow butts
- Regularly look up at trees for signs of danger
- Listen for the sound of moaning/cracking timber
- Be cautious in strong or gusty winds
- Avoid parking under trees
List and briefly describe the three main factors that affect the fire behaviour of a bushfire.
- Fuel; type/quantity/condition/arrangement
- Weather; temp/humidity/wind speed/wind direction
- Topography; shape/features of a landscape
Before a backburn is lit, the OIC must be satisfied conditions are met. What are five of these conditions?
- A satisfactory control line has been identified and established
- Adequate resources are present to light the backburn and prevent its escape
- Sufficient time exists for the backburn to be developed and penetrate far enough so that the junction zone effect and resultant spotting will not endanger the control line
- All personnel involved have been briefed on the plan, comms channels, and escape routes
- Backburn parameters and the likelihood of success have been calculated considering things such as fuel/terrain/weather/resources
What are the major advantages of making an indirect attack on a bushfire?
- Only method effective against large and intense fires
- Enables choices between the location of control lines
- Allows the use of defensible, existing barriers
- Allows time for the construction of control lines
- Crews are not affected by heat and smoke until backburning commences
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.
- Lookouts; lookouts maintain awareness of the environment immediately surrounding personnel
- Awareness; is the responsibility of all personnel, OIC/crew leaders responsible for ensuring common operating picture between personnel
- Communications; OIC/crew leaders responsible for establishing and maintaining effective comms
- Escape Routes; OIC/crew leaders responsible for identifying and communicating to crew a min. of 2 suitable escape routes
- Safety Zones; an area cleared of flammable material and large enough to provide adequate space for crew protection
List four 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
- Tape the insides of windows to retain integrity of glass cracked by radiant heat
- Move wooden/flammable outdoor furniture/objects away from the building
- Scatter woodheaps stacked against building walls
Backburning is a strategy used throughout Western Australia in fire suppression. It can be dangerous if carried out under the wrong conditions. List two disadvantages of using a back burn.
- It increases the total fire area
- If can endanger the lives of firefighters
How far should you keep from a bulldozer working in the forest?
- Minimum distance of 2.5 tree lengths clear of the average tree height in the area
Describe the Dead Man Zone and its potential consequences
- An area near the fire edge which can be consumed by a moving fire within five minutes due to a wind change
- Can change a low intensity, slow-moving flank fire into a high intensity, fast-moving head fire very quickly with little or no warning
- Potential for a burn over and serious injury or harm to firefighters
As a general rule, what is the maximum flame height that may allow a direct attack?
- 1.5m - 2m
Give a brief description of the three basic types of fires? (Ground, Surface, Crown)
- Ground; burn below the ground (i.e. peat, coal), burn slowly and can burn unnoticed
- Surface; most common, (i.e. grass, scrub), can have extreme spotting and ROS
- Crown; radiant heat and direct flame rising from the surface fire ignites the tops of trees above (and in front)
Summarise acceptable fuel and weather conditions for backburning?
- Remove fuels from around the base of trees near the edge to prevent fire running up trees (this reduces the risk of spotting)
- If possible, delay lighting until late afternoon or evening when weather conditions are more favourable (i.e. declining fire danger)
- Backburn against the wind where possible
- Backburning is too risky/hazardous if the weather is hot, dry, unstable or has a high Keetch-Byram Drought Index (KBDI) rating
When would a spot ignition pattern be used to light a backburn along the edge of a control line rather than using a line ignition pattern?
- Where it is essential that fire intensity be minimised
What is the blackout distance as per SOP 3.5.1 – Bushfire Response for the following fuel distribution types?
- Ground Fuels (grass, mulch, logs etc.) 20m
- Vertical Fuels (trees, structures, fencing etc.) 100m
In implementing a defensive strategy of asset protection what must be done immediately after the fire front has passed?
- Return to extinguish spot fires and burning structures
