Wildland Firefighting Flashcards
What are the four common denominators on fatal fires?
- Incidents occurred on small fires
- Flareups generally occurred in deceptively light fuels
- Chimneys, steep slopes
- Wind shift
Never work within 35 of high voltage wires and don’t spray water within 100’ of power poles.
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Weather is the primary driving force behind the changes in fire behavior
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Atmosphere closest to the ground is what
troposphere
What are the four primary factors that influence temperature?
- Amount of moisture or pollution in the air
- Angle between the surface and the sun
- The lag time between when solar radiation strikes the earth and when the heat is radiated back into space
- The surface properties of the terrain an vegetation
What is the greatest impact on fire behavior of any weather factor
Wind
A passage of a weather front is usually accompanied by a shift in wind direction
Statement
A passage of a warm front will usually do what to the wind direction? A cold front?
Warm shifts the wind 45 to 90 degrees
Cold shifts direction from less than 45 to as much as 180 degrees
What are the 4 types of winds?
- General winds - affect large areas / reported daily weather forecasts
- local winds - featured by terrain
- Surface Winds - measured 20’ above the ground
- Mid flame winds - measured at midpoint of the flame
The force of the earths rotation on the moving air causes the wind to move counter clockwise and clockwise south of the equator. What is this called
Coriolis force
What is pressure gradient?
The difference between the high and low pressure system
An area of low pressure is called a ?
Trough
What are some types of local winds
Sea breeze, land breeze, slope and valley winds
What is the difference between upslope and upvalley winds?
Upvalley winds do not start until most of the air in the valley is warmed.
What are the 4 types of problem winds?
- Cold front winds
- Foehn (fane) winds
- Thunderstorm downdrafts
- Whirlwinds / dust devils
As a cold front passes, winds shift rapidly to what direction
West… then northwest
As foehn wind flows downslope in the atmosphere it is compresses, becoming warmer and drier
Statement
How are Santa Ana winds created?
When a strong high pressure area in the Great Basin and a low-pressure area located above the Pacific Ocean along the Southern California coast
What are the four Foehn winds
- Santa Ana
- Chinook wind
- North winds
- Eastern winds
Where do the Chinook winds occur?
Rocky mountains
Thunderstorms have a life expectancy of about ____ hrs?
Less than 12 hrs
Whirlwinds are a sign of air being unstable
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Eastern winds are over Washington State and Oregon near the Cascade mountain range
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Gusty winds, good visibility and clouds growing vertically are all signs of what?
Unstable air
What is virga an indicator for?
thunderstorm has matured
Winds that influence the direction of the fire the most are which type of flames?
Mid flame
Relative humidity is the ratio of the amount of water vapor present in the air compared to the greatest amount possible at the same temperature
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RH represents how wet or dry the air actually is
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Dew point is the temperature at which the air is 100% saturated with water vapor
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Southern aspects are generally how many degrees hotter than northeast aspects?
5 degrees
Thick cloud cover can lower summer temps by how many degrees
15 to 20 degrees
What are the 3 types of lapse rates and how many degrees per 1000’ of elevation change?
5.5 degrees per 1000’ ft
What is the Haines index for?
Determine relative fire danger. Calculates the temp, dew point, and dryness at two levels in the atmosphere
A 5 or 6 on the Haines scale would indicate?
moderate to high fire danger
An inversion layer is a layer of very stable air where, contrary to normal behavior, the temperature rises as the altitude increases
Statement
Temperatures in an inversion layer may increase as much as ___ degrees per 1000’
15
A thermal belt is the “warm area”on a mountain slope associated with an inversion layer
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Inversion layera acts like a lid or blanket over cooler air.
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Cooling from below promotes stable air; heating from below promotes unstable air
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What are the 6 cloud types
- Cumulonimbus - thunder storm
- Cirrostratus - wispy clouds possible rain in a day or two
- Altocumulus castellanus - mid level. little towers
- Altocumulus floccus - whit gray tufts
- Lenticularus - lens shaped. lee side usually stationery
- Stratus - uniform, featureless low level
Four ways a thunderstorm is created
- Thermal lifting
- Orographic lifting
- Frontal lifting
- Convergence lifting
Three stages to a thunderstorm
Cumulus, mature, dissapating phase
Expect downdrafts with thunderstorm
Statement
3 principal elements affecting wildland fires
weather , fuels and topography
Fire will run ___ faster at a 30 degree slope. It will also run ___ times faster at 55% slope
2 times
4 times
Define aspect
The direction a slope is facing
Northern slopes heavy fuels with high moisture content. Eastern slope transitional. first to receive solar and first to cool in late afternoon. Southern have lighter flashy fuels with lowest moisture content. Western are transitional heating occurs in afternoon
Statement
Which type of heat transfer plays the biggest role in spread of wildland fire
Convection
What are the 3 types of fuels?
Ground fuels, surface fuels, aerial fuels
Surface fuels are fuels to about what height
6 ft
Aerial fuels are fuels from about what height and higher
6 ft and higher
Fuel loading is usually measured in tons per acre
Statement
Grassy fuels measure 1 to 5 tons per acre; Brush is 20 to 40 tons per acre; and slash is roughly 30 to 200 tons; timber is 100 to 600 tons per acre
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Fuel loading is divided into 4 classes, what are they?
- Grasses 0 to 1/4”
- Twigs 1/4” to 1”
- Branches 1 to 3”
4 Large branches more than 3”
Dead fuel moisture is the moisture content that is in dead material.
Statement
What are the 3 factors of fuel that spread fire
Moisture content, size and shape, and fuel loading
The smaller the fuel, the quicker the change in fuel moisture.
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What is time lag?
The time it takes for moisture content of fuels and the surrounding air to equalize
What is the dead fuel moisture time lag in relationship to the 4 sizes of files?
1 hr less than 1/4” grass
10 hr 1/4”-1” coastal sage
100 hr fuel 1”-3” logging slash
1000 hr 3”-8” logs - timber
What are the two types of living files?
Herbaceous and woody
Moisture content can range from 2-30% in dead fuels and 30-300% for live fuels.
Statement
Generally more than 1/3rd of grass has to be dead for a fire to be carried
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What are the three most important weather components/
Wind, temperature and relative humidity
What are the most important topographic components
steepness of slope and aspect
What are the most important factors of fuel components
fuel moisture and temperature
Combustion usually occurs at about 500 degrees in wildland fuels
Statmente
A chain is how many feet per hour
66
There are 7 factors that constitute the fire environment.
- Fuel charactreistics
- Fuel moisture
- Fuel temperature
- Topography
- Wind
- Atmospheric stability
- Fire behavior
In most areas, when the relative humidity gets below ___% in fine fuels fire burns with intensity. 10 hr fuels need less than 7% to burn intensly. 1000 hr fuel are 20% and they wil burn
25%
Generally wind of just ___ mile per hr can cause rapid rates of spread
10 mph
Indrafts winds move in to replace heated air that is lifted by the convetive action of the fire.
Statement
Downdrafts occur below the convective column.
Statment
One volume of water will cool 300 volumes of burning fuel
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Utilizing foam breaks down 3 sides of the fire triangel… Cool, smother, and insulate
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What is a long-stringed “super absorbent polymer that can absorb water at a ratio of at least 50 to 1
firefighting gel
What are some examples of a control line
streams, lakes, ponds, rock slides, roads
What is a cleared strip or portion of a control line from which falmmable material has been removed by scraping or digging down to mineral soil
Fireline
What is the running edge of the fire that is spreading with the greatest speed
head
What is the general rule for fireline width
1 1/2 times as wide as the predominant fuel is tall
Extreme fire behavior should be 2 times the width
Guidelines for width of firelines..
Grass 2 to 3 ft
Medium brush 4 to 6 ft
Heavy Brush 9 ft
What is it called with you use fire to remove the unburned fuels between the fire’s edge and the control line
Burning out or firing out
What is it when you indirectly attack tactic used to slow a fast burning fire.
Backfire
What is the key to backfiring?
The main fire draws in the backfire into it
Buring out is the most commonly used firing operation.
Statement
Buring out is a direct method of attack to secure holding lines, reduce mop up, to cut across fingers, incorporate spot fires.
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For backfiring, fire from the top down in steep terrain, fire into the wind, from the lee side or tops of ridges, from the bottom of wide canyons
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A backing fire is a low intensity fire that is allowed to back into the wind from the fireline. one of the safest ways to fire, draw back are wind shift, spotting, and amount of time it takes to comlete.
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What are some watch out situations for firing operations
- Adverse location with sharp bends
- narrow canyon through saddles
- Heavy fuels and snags near the line
- Weather is changing
- High value assets close
What is it called when you set a fire along the flanks of the fire. The wind is more of a fin this fire. Usually burn a little more than a backing fire
Flanking fire
What type of fire is ignited at a control line with the wind
Head Fire
What firing technique is used when you want to widen a fireline quickly. It’s set in parallel to the fireline in strips
Strip firing
Strip firing can be used in the 1-2-3 method. The firing order is dictated by the direction of slope and wind. Basically the strip furthest from the wind starts first.
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What type of firing is used when you are trying to save a valuable resource
Ring firing
What are some general rules for firing operations.
- Always begin firing from an anchor point except ring fire
- Begin at the head working down the flanks to the heel if you can
- Burn downhill if you can
Burn from back side of ridges ( not the top) - Burn into saddles simultaneously from both directions
An acre is how many square feet?
43,560
209 on each side
Determining rates of fire spread. a low, moderate, high and extreme move how fast?
- Low 100 ft per hour
- Moderate 100-400 ft per hour
- High 400-1800 ft per hour
- Extreme over 1800 ft
How do you calculate acreage using square footage
- Take average width
- Multiply that number by length
- take that number and divide by 43,560
Besides using the square footage for calculating acreage, what is the other method called
Dot grid
Direct attack method is working on the fire’s edge, the paralles attack method is where you contruct the fireline 6-50 ft away from fire’s edge. Indirect is where firline is constructed some distance from the fire
Statement
If the flame length is burning more than ___ ft its probably too intense for a direct attack.
4’
Direct attack is usually used on smaller fires and in the rear of larger fires
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What are the 4 direct attack deployment strategies
- Flanking attack
- Tandem action
- Pincer action
- Envelopment action
What is flanking action
Picking an anchor point and extinguishing one side of the fire
What is a Tandem attack
When an attack involves two or more resources to fight fire
What is Pincer attack
Both flanks are attacked at the same time working together from opposite sides to cut the head off
What is envelopement attack
When the fire is attacked from all different sides
The parrallel attack method constructs line close to the fires edge (6 to 50 ft). The line is immediately burned-out after construction. You carry the fire with you as you go.
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The indirect attack differs from the parallel attack in that the line is not bured-out as you go.
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What is hot spotting
A dangerous tactic for helitac crews to cut a scratch line around the hot spots or fingers to slow the fire down
What is cold trailing
Working along a partially dead line looking for hotspots or improving the existing or cutting new line when necessary
Minimum standards for strike teams engine GPM and water tank size
Type 1 1000 GPM 400 gallons
Type 3 150 GPM 500 gallons
For every 1000’ in elevation, there is a loss of one foot in suction or lift. + or - 43 psi for change of 100 of elevation
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When are airtankers most effective of a wildland fire
Initial attack phase
Airtankers can carry 3000 gallons of retardant and Siskorkies sky crans cary 2000 gallons of water
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Airtankers should have less than a ___ minute turno around time and helicopters should have less than a ____ turn around time
30 minutes
10 minutes
The national guard MAFFS can drop ____ gallons of retardant
3000
What is the best drop height for retardant
150 ft
Type I, II, III, and IV tankers can drop how many gallons?
Type 1 3000 or more
Type 2 1800 to 3000
Type 3 800 to 1799
Type 4 100 to 799
The approach clearance and departure clearance fo a helicopter on a water point is
100’ and 300’
20x20 pad with 100’ safety circle
Type I handcrews have min of 80 hrs and have 18-20 personnel.
Statement
As a rule of thumb, a 15-person crew should be able to construct a 3 ft wide fireline around a one acre fire in one hour
Statement
Best place for dozer work is on ridge tops.
Statement
A safeety circle of ___ ft around a dozer
50’
The topographic map is a graphic representation of the 3 dimesions of the the earths surface. Vertical dimension being indicated by contour lines
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Three elements to fire prevention components
Education, enginering, and enforcement
Hand crew in grass can cut 3’ wide at 900’ per hour
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Hand crew medium brush can cut 6’ wide at 450’ an hour
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Hand crew heavy brush can cut 9’ wide at 300’ per hour
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