S-190 Module 2 (2 of 2. Principles of
Wildland fire Behavior)
The, (blank), of cumulus clouds indicate the depth and intensity of the instability. -
answer Height
(Blank), clouds, often called thunderheads often indicate strong, gust winds that shift
erratically as a storm passes. - answer Cumulonimbus Clouds
(Blank), clouds indicate stable layers in the atmosphere with little or no winds. - answer
Stratus Clouds
What is an "inversion layer"? - answer An inversion layer is when the temperature
actually increases with height. In such situations, the air is said to be stable as along as
the inversion is present.
Under an inversion, fuel moisture content is usually, (blank), decreasing ROS & fire
intensity. - answer Higher
What are three indicators when an inversion breaks? - answer1. Increase in
temperature
2. Decrease in RH; &
3. Increase or shift in wind
What are 3 types of inversion? - answer1. Night inversions
2. Subsidence inversions; &
3. Marine inversions
Inversions can often be spotted because you see a, (blank), of clouds or smoke hanging
over a surface. - answerLayer
Night inversions are not only affected by the cool air moving in during nighttime hours,
but also by: - answerTopography, Temperature, & Humidity.
Measurements of, (blank), &, (blank), can indicate the strength of a night inversion. -
answerTemperature & Humidity
In the absence of a visible smoke or cloud layer, the top of the inversion can be found
by measuring, (blank), at various points up and down the slope. - answerTemperatures
, What is a "thermal belt"? - answerA thermal belt is the top of an inversion layer. This
area has the warmest air temperature and also has the lowest nighttime relative
humidity & moisture content.
(Blank), the thermal belt, fires are in cool, humid, & stable air, often with downslope
winds. - answerBELOW
What are "subsidence inversions"? - answerSubsidence is the large-scale sinking of air
associated with high-pressure systems and usually contributes in the development of
foehn winds.
Burning conditions can become severe during, (blank), inversions because skies are
typically clear or cloudless and extended periods of above-average temps & below-
average RH can dry out fuels. - answerSubsidence Inversions
(Blank), inversions are common in the summer and may be caused when winds reverse
at night and become a land breeze. - answerMarine Inversions
Inversions on the, (blank) coast are called marine inversions. - answerWest Coast
Air is extremely, (blank), in an inversion layer. - answerStable
(Blank), decreases both above and below in an inversion layer. - answerTemperatures
What are 4 indicators of an unstable atmosphere? - answer1. Clouds grow vertically
and smoke rises to great heights.
2. Cumulus clouds a represent
3. There is good visibility; &
4. Gusty winds and dust devils or fire-whirls
Define "wind"? - answerWind is basically air in motion and is measured in terms of:
direction, speed, & turbulence.
What are the two most important weather-related elements affecting wildland fire
behavior? - answerWind & Fuel Moisture. Wind is the least predictable.
(Blank), behavior largely determines the rate and direction of spread for a wildland fire. -
answerWind
Wind has both, (blank), &, (blank), effects - answerDirect & Indirect Effects
What are the three essential types of winds? - answer1. General Winds
2. Local Winds; &
3. Convective Winds
Wildland fire Behavior)
The, (blank), of cumulus clouds indicate the depth and intensity of the instability. -
answer Height
(Blank), clouds, often called thunderheads often indicate strong, gust winds that shift
erratically as a storm passes. - answer Cumulonimbus Clouds
(Blank), clouds indicate stable layers in the atmosphere with little or no winds. - answer
Stratus Clouds
What is an "inversion layer"? - answer An inversion layer is when the temperature
actually increases with height. In such situations, the air is said to be stable as along as
the inversion is present.
Under an inversion, fuel moisture content is usually, (blank), decreasing ROS & fire
intensity. - answer Higher
What are three indicators when an inversion breaks? - answer1. Increase in
temperature
2. Decrease in RH; &
3. Increase or shift in wind
What are 3 types of inversion? - answer1. Night inversions
2. Subsidence inversions; &
3. Marine inversions
Inversions can often be spotted because you see a, (blank), of clouds or smoke hanging
over a surface. - answerLayer
Night inversions are not only affected by the cool air moving in during nighttime hours,
but also by: - answerTopography, Temperature, & Humidity.
Measurements of, (blank), &, (blank), can indicate the strength of a night inversion. -
answerTemperature & Humidity
In the absence of a visible smoke or cloud layer, the top of the inversion can be found
by measuring, (blank), at various points up and down the slope. - answerTemperatures
, What is a "thermal belt"? - answerA thermal belt is the top of an inversion layer. This
area has the warmest air temperature and also has the lowest nighttime relative
humidity & moisture content.
(Blank), the thermal belt, fires are in cool, humid, & stable air, often with downslope
winds. - answerBELOW
What are "subsidence inversions"? - answerSubsidence is the large-scale sinking of air
associated with high-pressure systems and usually contributes in the development of
foehn winds.
Burning conditions can become severe during, (blank), inversions because skies are
typically clear or cloudless and extended periods of above-average temps & below-
average RH can dry out fuels. - answerSubsidence Inversions
(Blank), inversions are common in the summer and may be caused when winds reverse
at night and become a land breeze. - answerMarine Inversions
Inversions on the, (blank) coast are called marine inversions. - answerWest Coast
Air is extremely, (blank), in an inversion layer. - answerStable
(Blank), decreases both above and below in an inversion layer. - answerTemperatures
What are 4 indicators of an unstable atmosphere? - answer1. Clouds grow vertically
and smoke rises to great heights.
2. Cumulus clouds a represent
3. There is good visibility; &
4. Gusty winds and dust devils or fire-whirls
Define "wind"? - answerWind is basically air in motion and is measured in terms of:
direction, speed, & turbulence.
What are the two most important weather-related elements affecting wildland fire
behavior? - answerWind & Fuel Moisture. Wind is the least predictable.
(Blank), behavior largely determines the rate and direction of spread for a wildland fire. -
answerWind
Wind has both, (blank), &, (blank), effects - answerDirect & Indirect Effects
What are the three essential types of winds? - answer1. General Winds
2. Local Winds; &
3. Convective Winds
