S-190 Save
Terms in this set (83)
Wildland/Urban Interface Line, area, or zone where structures and other human
development meet or intermingle with undeveloped
wildland or vegetative fuels.
Convection Column Rising column of heated air or gases above a continuing heat
or fire source.
Fire Spread Since there are 60 minutes in an hour and just over 60 ft. (18
m) in a chain, using the rule of thumb will give you a
reasonably accurate measurement of the fire's forward
progress. For example:
1 ft. (0.3 m)/minute = 1 chain/hour
10 ft. (3 m)/minute = 10 chains/hour
A fire that burns an area 10 chains by 10 chains is a 10-acre
fire.
,Conduction When two objects of different temperatures contact each
other directly or through a medium, heat conducts from the
warmer object to the cooler one until their temperatures
equalize.
Convection Hot convected gases moving up a slope can dry out fuels
lowering their ignition temperature. These fuels also become
preheated by the convected heat, thus increasing their
susceptibility to ignition and more rapid fire spread.
Radiation 1—Heat waves, sometimes called infrared rays, radiate in all
directions from the heat source.
2—Heat waves travel through air until they are totally or
partially absorbed by an opaque object.
3—The opaque object gains heat and in turn radiates heat
from its surface.
Aspect The aspect of a slope determines the effect of the sun's heat
on the slope's plants and trees, air temperature, and moisture
retention of the soil. Solar radiant heating can influence fire
behavior by influencing fuel moisture and ignition points. The
southern slopes are more susceptible to fires than northern
slopes.
, Slope -Uphill side of a fire—flames are closer to the fuel
dehydrating, preheating, and igniting them sooner than they
would if they were on level ground
-Wind currents normally move uphill during the day and tend
to push heat and flames toward new fuels
-Upslope fires create a draft, increasing the ROS. One
serious concern about fires burning down steep slopes is the
possibility of burning material rolling downhill, which can
ignite fuels below starting another fire.
Calculating Slope The percentage of slope is based on the ratio of vertical rise
to horizontal distance.
To calculate a slope's percentage, follow these steps:
1. Measure the amount of vertical elevation change then...
2. Divide that number by the horizontal distance and...
3. To change the final number into a percent, multiply by 100.
Saddle Depression or pass in a ridgeline; low area on a ridgeline
between two higher points.
Chute A chute is a steep V-shaped drainage
Chimney Steep, narrow draws or canyons in which heated air rises
rapidly as it would in a flue pipe.
Terms in this set (83)
Wildland/Urban Interface Line, area, or zone where structures and other human
development meet or intermingle with undeveloped
wildland or vegetative fuels.
Convection Column Rising column of heated air or gases above a continuing heat
or fire source.
Fire Spread Since there are 60 minutes in an hour and just over 60 ft. (18
m) in a chain, using the rule of thumb will give you a
reasonably accurate measurement of the fire's forward
progress. For example:
1 ft. (0.3 m)/minute = 1 chain/hour
10 ft. (3 m)/minute = 10 chains/hour
A fire that burns an area 10 chains by 10 chains is a 10-acre
fire.
,Conduction When two objects of different temperatures contact each
other directly or through a medium, heat conducts from the
warmer object to the cooler one until their temperatures
equalize.
Convection Hot convected gases moving up a slope can dry out fuels
lowering their ignition temperature. These fuels also become
preheated by the convected heat, thus increasing their
susceptibility to ignition and more rapid fire spread.
Radiation 1—Heat waves, sometimes called infrared rays, radiate in all
directions from the heat source.
2—Heat waves travel through air until they are totally or
partially absorbed by an opaque object.
3—The opaque object gains heat and in turn radiates heat
from its surface.
Aspect The aspect of a slope determines the effect of the sun's heat
on the slope's plants and trees, air temperature, and moisture
retention of the soil. Solar radiant heating can influence fire
behavior by influencing fuel moisture and ignition points. The
southern slopes are more susceptible to fires than northern
slopes.
, Slope -Uphill side of a fire—flames are closer to the fuel
dehydrating, preheating, and igniting them sooner than they
would if they were on level ground
-Wind currents normally move uphill during the day and tend
to push heat and flames toward new fuels
-Upslope fires create a draft, increasing the ROS. One
serious concern about fires burning down steep slopes is the
possibility of burning material rolling downhill, which can
ignite fuels below starting another fire.
Calculating Slope The percentage of slope is based on the ratio of vertical rise
to horizontal distance.
To calculate a slope's percentage, follow these steps:
1. Measure the amount of vertical elevation change then...
2. Divide that number by the horizontal distance and...
3. To change the final number into a percent, multiply by 100.
Saddle Depression or pass in a ridgeline; low area on a ridgeline
between two higher points.
Chute A chute is a steep V-shaped drainage
Chimney Steep, narrow draws or canyons in which heated air rises
rapidly as it would in a flue pipe.
