Wildland firefighting S-190
Thermal belt
Top of an inversion layer
Convection
Transfer of heat by fluid or gases. Usually upward direction.
Night inversions
Trap smoke and make for poor visibility. Dissipate when the sun rises.
Unaffected area between the main fire and finger.
The green
Unburned area close to the fire where live or dead fuels are. NOT SAFE
Islands
Unburned areas inside the perimeter.
Wildland fires
Unplanned or unwanted fires.
Topography
Land surface configuration; terrain
Land breeze at night
Land surface cools faster than water surface. Land to water directions
Subsidence
Large scale sinking of air associated with high pressure.
West facing slope
Later heating and cooling within the day. Sunrise and sunset
Live fuels
Living plants, high moisture vegetation, low moisture content
Heavy fuels
Logs, large limbs, not easy to ignite. Burn hot, long and slow
Fingers
Long narrow strips of fire that break off of the main fire. Caused by mixed fuels, natural features dividing the fire.
Creeping fires
Low flame. Burns slowly
Remove fuel
Make a fireline.
Cold front
Makes controlling a fire very difficult.
Mop up
Making the fire safe after it's controlled.
Fire behavior
Manner in which the fire reacts to various fuels, weather and topography.
Slopover/ Breakover
When fire crosses a control line
Fire crowning
When the fire spreads across the tree tops faster than the surface Fire.
Wind and fuel moisture
2 most important weather replayed elements affecting wildland fires.
Fireline
A section where flammable material has been removed or scraped by digging down to soil.
Flare up
Short time and doesn't change existing control plans.
Flanks
Sides of a wildland fire. May change to the head or fingers might form because of fuel.
Convective winds
Slope and valley winds, land and sea breezes, thunderstorm winds, whirlwinds, firewhirls
When can blow and flare ups occur?
Smaller fires, isolated portions of big fires. When the fire is calm and innocent.
Spot fires
Smalls fires burning beyond main fire boundary.
Removing oxygen
Smothering the fire with dirt.
What cause flare ups?
Air blasts from helicopters and air tankers.
Loading
Amount of live and dead fuel in a specific area.
Foehn wind
Santa Ana winds. Air being forced over ridges from convection or high barometric pressure.
Combustion
Self sustaining process of a fuel that produces heat and light.
Conduction
Tranfer of heat by direct contact. Ex: hot exhaust touching brush
Direct effect of wind
Intensifies the fire by feeding it more oxygen. Bends flames. Carries embers.
Reburns
Wind shift or a fire moves fast and doesn't burn everything.
The Black
Area where fire has already moved through.
Slope
Bad: uphill. Pre heats fuel and burns faster. Good: uphill moving down. Doesn't preheat fuel and moves slower.
Firebrand sources
Blurring materials carried by the wind. Ex: maple and oak leaves
Firewhirls
Burn intensely, can create spot fires, occur on protected side of elevated terrain features, more dangerous than dust devils.
Smoldering
Burning without flame. Moves slowly.
Box canyons
Chimney effect on a canyon
Uniform fuels
Close together and spread evenly over an area.
Control a fire
Complete control line around fire, burn out Unburned areas on the opposite side of the line, cool down hot spots.
Control line
Constructed or natural fire barriers. Also describes treated fire edges.
Indications when observing fuels around the fire
Continuous fine fuels, heavy loading of dead and down fuels, ladder fuels, tight crown spacing.
Numerous snags
Dead/ partially dead trees
Solid fuels
Dust, coal, wood, paper, plastic,hay, cork,sugar,grain.
East facing slope
Early heating in the morning. Early cooling in evening.
Unstable atmosphere
Encourages upward motion pushing cold air over warm air. Increased fire activity. See cumulus clouds. Dust devils
Light fuels
Fast drying. Usually in a shallow flame front. High surface area to volume ratio. Less than 1/4 in diameter easily ignite and burn rapidly
Slope winds
Flow up during the day due to surface heating, flow down during the night due to surface cooling.
7 fire environment factors
Fuel characteristics, fuel moisture, fuel temp, topography, wind, atmosphere stability, fire behavior
Aerial fuels
Fuel suspended from the ground. Ex: branches, twigs, bark and vines.
Surface/ Ground Fuel
Fuel that contacts the ground. Ex: leafs, dead branches, bark, tree cones.
Fire Triangle
Fuel, oxygen and heat
Liquid fuels
Gasoline, kerosene, alcohol, paint,
Frontal winds
Goes across the earths surface. Cold warm fronts.
Atmospheric instability
Good visibility, strong winds/ dust devils, cumulus clouds, castellatus clouds in the morning, smoke rising straight up, inversion begins to lift, thermal belt
Head
Greatest rate of spread. Moves intensely. May have more than one head.
Fuel size
Help predict how specific weather conditions will affect rate of heat transfer
Fuel moisture
Helps firefighters predict how the fire will behave
Fuel position
Helps firefighters predict how the fire will behave
Size and shape
Helps predict the rate of spread
Dust devils
Hot days, flat dry surfaces, skies are clear and winds are light. Cause spotting.
Rate of Spread ROS
How fast the fire is moving. Measured in chains or acres per hour.
Chain
How the fire is measured. 60ft in a chain. Ex: 1ft/min= 1 chain per hour 10ft/min= 10 chains per hour
North facing slopes
More shade. Heavier fuels, low temp, high humidity, high fuel moisture. Less fire activity than south.
South facing slope
Most hot slope. Results in high temp, low humidity, loss of fuel and soil moisture, dry fuel like grass. More susceptible to fires than north slopes.
Fire spread
Movement of the fire.
Slope aspect
NESW
Gas fuels
Natural gas, propane, butane, hydrogen,acetylene, carbon monoxide.
Torching fire
Not as serious as a crown fire. Ignites tree tops for a bit then goes back to surface fire
Wide canyons
Not common for spotting but will occur on N S facing aspects
Rear/ heel
Opposite to the head of the fire. Close to the point of origin.
Perimeter
Outer boundary of burning or burnt area.
Fireline
Part of the control line. Dug to mineral soil. Where firefighting activities take place.
Frost and bug kill
Provide fuel for a fire
Inversion
Reduce fire activity
Convection column
Rise of heated air or gases above a continuing heat or fire.
Convection column
Rising hot air/ gas above the fire source.
Natural barriers
Rivers lakes rocks burned area swamps
Man made barriers
Roads highways reservoirs firelines
Subsurface fuels
Roots
Firewhirl
Spinning columns of rising air and fire gases. Carry smoke, debris and flames. Can cause spotting. 1-500ft in diameter.
Narrow canyons
Spread to the other side by radiation and spotting.
Running fire
Spreads rapidly. Well defined head.
Landward sea breeze
Start in the Morning, strengthen in the afternoon, die down in the evening.
5 indicators when assessing terrain
Steep slopes, chutes, saddles, box canyons, narrow canyons
Black unsafe
Steep terrain, hot spots, falling snags, exposure from adjacent Unburned fuels.
Chute
Steep v shape drainage
Indirect effects of wind
Strong, dry winds absorb moisture from fuel. Cool winds can retain moisture. Wind changing, making the fire change rapidly.
Blowup
Sudden increase in ROS. Can behave like fire storms.
7 indicators of wind
Surface winds above 10mph, shifting wins, lenticular clouds, high fast moving clouds, cold fronts, cumulonimbus clouds, sudden calm
Removing heat
Water or class A foam
Flaming front/ Fire front
Where continuous combustion is taking place within a fire. Leading edge of fire perimeter. Surfaces fires= smoldering combustion.
Dead fuels
Where moisture is only governed by only atmospheric moisture. Ie: relative humidity and precipitation.
Origin
Where the fire started and or where it's going.
Anchor points
Where you should start your fireline. Minimizes the chance of being outflanked by the fire when the line is being built.
Fire Suppression
Work connections with putting out the fire.