S-290. Unit 6
6.1: Describe the relationship among atmospheric pressure, temperature, density, and
volume. - answer Pressure = density*temperature. Density = Mass/volume
6.2: Describe temperature lapse rate and stability, and the different lapse rates used to
determine the stability of the atmosphere. - answer Dry adiabatic: 5.5
Wet: 3
Average: 3.5
6.3: Describe the effects of atmospheric stability on wildland fire behavior. - answer
Unstable air = more active wildland fire behavior by increasing:
Likelihood of fire whirls and dust devils
Likelihood of gusty and erratic surface winds
The height and strength of convection and smoke columns
Likelihood of firebrands being lifted to great heights for long-range spotting
Stable air = less active wildland fire behavior by:
Limited rise of smoke columns
Reducing inflow of fresh air, limiting growth of wildland fire and their convective column.
Lowering surface wind speeds and fire spread rates (except in mountainous terrains)
6.4: Name 4 types of temperature inversions and describe their influence on wildland
fire behavior, including the thermal belt. - answer1. Nighttime or radiation inversion
Thermal belt forms when a nighttime inversion makes frequent contact wall or mountain
slope.
2. Frontal inversion
3. Marine inversion
4. Subsidence inversion
6.5: Name and describe the four lifting processes that can produce thunderstorms. -
answerThermal (convective)
Frontal lift
Orographic
Jet stream
6.6: Describe the elements of a thunderstorm and its three stages of development. -
answerThe 3 elements of a thunderstorm:
Moisture
Lifting
Instability
Three stages of development:
Cumulus: updrafts only.
Mature: downdrafts and updrafts. Lighting and thunder is seen.
6.1: Describe the relationship among atmospheric pressure, temperature, density, and
volume. - answer Pressure = density*temperature. Density = Mass/volume
6.2: Describe temperature lapse rate and stability, and the different lapse rates used to
determine the stability of the atmosphere. - answer Dry adiabatic: 5.5
Wet: 3
Average: 3.5
6.3: Describe the effects of atmospheric stability on wildland fire behavior. - answer
Unstable air = more active wildland fire behavior by increasing:
Likelihood of fire whirls and dust devils
Likelihood of gusty and erratic surface winds
The height and strength of convection and smoke columns
Likelihood of firebrands being lifted to great heights for long-range spotting
Stable air = less active wildland fire behavior by:
Limited rise of smoke columns
Reducing inflow of fresh air, limiting growth of wildland fire and their convective column.
Lowering surface wind speeds and fire spread rates (except in mountainous terrains)
6.4: Name 4 types of temperature inversions and describe their influence on wildland
fire behavior, including the thermal belt. - answer1. Nighttime or radiation inversion
Thermal belt forms when a nighttime inversion makes frequent contact wall or mountain
slope.
2. Frontal inversion
3. Marine inversion
4. Subsidence inversion
6.5: Name and describe the four lifting processes that can produce thunderstorms. -
answerThermal (convective)
Frontal lift
Orographic
Jet stream
6.6: Describe the elements of a thunderstorm and its three stages of development. -
answerThe 3 elements of a thunderstorm:
Moisture
Lifting
Instability
Three stages of development:
Cumulus: updrafts only.
Mature: downdrafts and updrafts. Lighting and thunder is seen.
