Fire Behavior & Weather Flashcards
7 cards from real RED CARD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fire Behavior & Weather flashcards as text
What does the term 'fire environment' encompass when analyzing wildland fire behavior?
Answer: The interaction of topography, fuels, and weather that collectively drive fire behavior
The fire environment triangle consists of topography, fuels, and weather—all three interact simultaneously to determine how a fire behaves at any given moment.
How do 'outflow winds' from a thunderstorm affect a nearby wildland fire?
Answer: They produce sudden, strong, erratic gusts that can cause explosive fire runs and unexpected direction changes
Thunderstorm outflows are cold, gusty, erratic winds that rush outward from a collapsing storm cell and can dramatically and unpredictably accelerate fire spread or cause sudden direction reversals.
What is 'backing fire' and how does its behavior differ from a 'heading fire'?
Answer: A backing fire spreads against the wind or downslope, burning more slowly and with less intensity than a heading fire
A backing fire spreads into the wind or downslope, resulting in lower flame lengths, slower rate of spread, and reduced intensity compared to the main heading fire that travels with the wind.
Why is a steep, narrow canyon considered a high-risk terrain feature during wildland fire operations?
Answer: Canyons channel and accelerate wind, create updraft tunnels for fire, and limit escape routes for firefighters
Steep narrow canyons function as natural chimneys that funnel and accelerate wind, dramatically increasing fire spread rate upslope while trapping firefighters who have limited escape routes.
What is 'flame length' and why is it used as a fire behavior indicator?
Answer: The distance from the base of the flame to its tip, indicating fire intensity and safe suppression tactics
Flame length is measured from flame base to tip and directly indicates fire intensity; tactical guidelines specify that direct attack becomes unsafe at flame lengths above 4 feet and impossible above 8 feet.
Which atmospheric layer characteristic makes the 'mixing height' important for fire weather forecasters?
Answer: It defines how deep the convective mixing layer is, affecting wind transport to the surface and smoke dispersal
Mixing height defines how deep the layer is within which surface heating drives vertical air mixing; a high mixing height allows stronger upper-level winds to mix down to the surface, increasing fire danger.
How does the 'aspect' of a slope (its compass-facing direction) influence fire behavior through fuel conditions?
Answer: South and west-facing slopes receive more solar radiation, creating drier, sparser fuels that support faster fire spread
South and southwest-facing slopes receive intense afternoon sun, resulting in drier soils, sparser vegetation, lower fuel moisture, and conditions that promote faster and more intense fire spread.