Chapter 2 Flashcards

1
Q

Define fire environment and behavior

A

Environment: conditions that determine the behavior of a fire. Based on fuel, weather, topography.

Behavior: manner which fuel ignites, flames develop, and fire spreads. Includes other fire phenomena determined by fuel/weather/topography.

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2
Q

Relative humidity

A

(RH%): moisture in the air relative to the total amount of moisture air can hold at a given temperature. Higher temperatures can hold more moisture.

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3
Q

Atmosphere stability

A

Measured by vertical movement of air. Unstable atmosphere incl vertically developed clouds > precursor for storms. Stable resists vertical movement and may reduce or suppress fire.

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4
Q

Orographic lift

A

Movement of storm over mountain ranges. Relative humidity reaches precipitation followed by rain shadow effect on leeward side.

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5
Q

Fuel moisture content

A

Amount of moisture in fuel represented by (wet weight-dry weight)/dry*100

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6
Q

Foliar moisture content

A

Moisture content of live foliage in canopy. Follows seasonal pattern depicted by dip in spring moisture content from new growth

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7
Q

Equilibrium moisture content

A

Occurs when there is no net gain or loss of moisture between fuels and surrounding air

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8
Q

Time lag to equilibrium

A

Describes responsiveness of fuels. Effected by %RH and C = time lag varies

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9
Q

Five stable fuel properties

A

Shape/size, load, compaction, distribution/continuity, position/arrangement

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10
Q

Six fuel strata

A

Subsurface, ground, surface, ladder, aerial, crown

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11
Q

Six topographic properties that influence fire behavior

A

Terrain, slope, aspect, elevation/slope, topographic features, barriers to spread

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12
Q

Time and space associated with fire triangle, fire behavior triangle, and fire regime triangle

A

Generally, time moves from seconds/minutes > hours/weeks/days > decades/centuries. Space moves from a microsite > local > landscape > region.

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13
Q

How does surface-area to volume ratio of the fuels affects fire behavior?

A

Influences rate a fire spreads. Fuels with a higher surface area to volume ratio, such as fine fuels, burn faster than heavy fuels.

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14
Q

How does aspect affect fuels, fuel moisture and potential fire behavior?

A

Determines amount of solar radiation received, fuel load potential, and fuel load moisture

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15
Q

What happens to fire behavior when a cold front passes over an active fire?

A

Creates unstable atmospheric conditions which are favorable for burning environment.

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