S-190 Intro to Wildland Fire Behavior Latest Update 2025-2026 330 Questions and 100% Verified Correct Answers Guaranteed A+
3 elements of the fire triangle - CORRECT ANSWER: Fuel to burn
Air to supply oxygen for the flame Heat to start and continue the combustion process
3 main objectives to fight a fire - CORRECT ANSWER: Anchor, Flank, Pinch
3 methods of heat transfer - CORRECT ANSWER: Radiation, convection, conduction
- Factors of look up, down and around: Fuel Characteristics - CORRECT ANSWER: -
Continuous fine fuels: Fire is able to change and spread rapidly in these fuels, especially when combined with slope and/or wind
-Heavy loading of dead and down: Large amounts of readily available fuel
-Ladder Fuels: Allow the fire to readily spread into the canopy, launching firebrands (spots) into the air
-Tight crown spacing: Allows fire to move from bush to bush easier
-Special conditions: Firebrand sources (pine bark plates, manzanita leaves, eucalyptus leaves, maple leaves, oak leaves), numerous snags, frost and bug kill, preheated canopy, unusual fine fuels, high dead to live ratio
- Factors to look up, down and around: Atmospheric Stability - CORRECT ANSWER:
Indicators of unstable atmosphere:
-good visibility -gusty winds and dust devils -cumulus clouds 1 / 4
-castellatus clouds in the am -smoke rises straight up -inversion beginning to life -thermal belt
- Factors to look up, down and around: Fire Behavior - CORRECT ANSWER: -Leaning
column -Sheared column -Well-developed column
-Changing column: behavior is usually increasing
-Trees torching: fire is beginning to transition from surface to crown
-Smoldering fire picking up: behavior is increasing, also possible that: inversion is lifting, wind is increasing, RH is decreasing, shading has decreased on that aspect -Small firewhirls beginning -Frequent spot fires
- Factors to look up, down and around: Fuel Moisture - CORRECT ANSWER: -Low RH
(<25%): lower humidity means the more available fine fuels to carry fire
-Low 10hr FMC (<6%): 10hr fuels are just one good indicator of how available fuels are to burn -Drought conditions and seasonal drying: both are indicators that fuels are more receptive to ignition and carrying the spread of fire
- Factors to look up, down and around: Fuel Temperature - CORRECT ANSWER: -High
temps (>85F) -High percent of fuels with direct sun -Aspect fuel temperature increasing: Which slopes tend to have higher fuel temps in the morning? In the afternoon?-S and SW slopes 2 / 4
-normally more exposed to sunlight -have lighter and sparser fuels -Most critical in terms of start and spread of fire
- N facing slopes
-heavier fuels -lower temps -higher humidity and fuel moistures
- Factors to look up, down and around: Topography - CORRECT ANSWER: -Steep
slopes (>50%) -Chutes-Chimneys: provides potential for rapid rates of fire spread by combining steep terrain with updrafts of air
-Saddles: Fire is pushed faster through these during uphill runs
-Box Canyons: All provide for rapid rates of fire spread due to the channeling of wind and heat -Narrow Canyons: Radiant and convective heating could increase spotting across the canyon
- Factors to look up, down and around: Wind - CORRECT ANSWER: -Surface winds
about 10mph
-Lenticular clouds: indicates high winds aloft with the potential to surface
-High, fast moving clouds: indicates potential for wind shifts
-Approaching cold fronts -Cumulonimbus development: indicates possible wind speed and direction and potential for erratic winds
-Sudden calm: be alert for wind change
Battling or shifting winds: winds that change direction and go back to the original direction are battling. This is an indication of probably change in wind speed and direction
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Aerial Fuels - CORRECT ANSWER: All green and dead materials located in the upper canopy Torching, crowning, spotting
Anchor point - CORRECT ANSWER: An advantageous location, usually a barrier to fire spread, from which to start constructing a fireline. Used to minimize the chance of being flanked while line is being constructed.
Aspect - CORRECT ANSWER: The direction a slope is facing (its exposure in relation of the sun
Aspect in terms of N, S, W, E slops - CORRECT ANSWER: N- have more shade; lowest rate of spread; late snow melt; later curing of fuels; heavier fuels; higher humidity; lower temps S- More exposed to sunlight; lighter and sparser fuels; high temps; higher rate of spread; early curing of fuels; lower humidity; these are most critical in terms of start and spread of wildland fires W- Later heating and cooling E- Earlier heating and cooling
Atmospheric Stability - CORRECT ANSWER: The degree to which vertical motion in the atmosphere is enhance or suppressed. Stability is directly related to the temperature distribution of the atmosphere Wildfire are greatly affected by atmospheric motion and the properties of the atmosphere that affect its motion
Backing fire - CORRECT ANSWER: That portion of the fire with slower rates of spread.Also called the heel
Barriers - CORRECT ANSWER: Any obstruction to the spread of fire, typically an area or strip lacking any flammable fuel
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