EAPS 106 - EXAM 3 QUESTIONS AND
ANSWERS
What (chemically) is fire? - Correct Answers -an exothermic, self-perpetuating chemical
reaction initiated by a small amount of heat
What is an exothermic chemical reaction? - Correct Answers -a reaction that releases
more energy than it absorbs (ie. heat producing)
What are the four components of the fire tetrahedron? - Correct Answers -1. fuel
2. heat energy
3. oxygen
4. uninhibited chain reaction
Name the phases of a fire in order. - Correct Answers -pre-ignition, combustion,
smoldering
What is the pre-ignition phase? - Correct Answers -heat causes fuels to give off vapors
that can burn
What is the combustion phase? - Correct Answers -fuels vapors combine with oxygen in
a reaction that releases more heat
What is the smoldering phase? - Correct Answers -ash cover leads to slow, low-
temperature burning and prevents new fuels from igniting
What is a surface fire? - Correct Answers -a fire that occurs in grasses, pine needles,
and shrubs near to the ground
What enables surface fires and crown fires to burn easily and spread quickly? - Correct
Answers -their fuels have a large surface area to volume ratio (lots of exposed area to
react with oxygen)
What is a crown fire? - Correct Answers -a fire that occurs near and at the crowns of
trees (canopy) where fine branches and needles burn very quickly
, Which type of fire moves the fastest and burns the hottest? - Correct Answers -crown
fire
What starts most wildfires in the US? - Correct Answers -humans start 85% of all
wildfires
What natural phenomenon most often causes wildfires? - Correct Answers -lightning
Why do wildfires started by lightning tend to burn a larger area? - Correct Answers -they
often:
- occur in remote areas
- burn longer before being noticed
- are more difficult to fight
- are often left burn as a natural process
What factors influence to potential of a wildfire to spread? - Correct Answers -- type of
vegetation
- amount of rainfall (less rainfall => more spread)
- average temperature (higher temperature => dryer fuels => more spread)
- topography (steeper slopes => more spread)
- wind strength
What type of vegetation has most potential to burn and where is it found? - Correct
Answers -desert shrubs, between the west coat and mid-west
Does fire burn the fastest uphill or downhill? - Correct Answers -uphill
Where in the US has the greatest potential for wildfires to spread? - Correct Answers -
the deserts and mountains of the west
How fast can wildfires move (at top speed)? - Correct Answers -up to 80 mph
What is the largest wildfire in US history? - Correct Answers -the Great Fire of 1910:
burned 3 million acres in 2 days, killed 87 people including 78 firefighters, led to the
"fight all fires" policy of the National Forest Service
What was the original policy of the US forest service toward fighting wildfires? - Correct
Answers -fight them whenever and wherever they occur
What is the current policy of the US forest service toward fighting wildfires? - Correct
Answers -let them burn in "primitive" areas unless they endanger people or structures
What does the US forest service allow some wildfires to burn? - Correct Answers -to
prevent the build up of fuels over time; this allows natural fires to consume fuels which
prevents more catastrophic fires
ANSWERS
What (chemically) is fire? - Correct Answers -an exothermic, self-perpetuating chemical
reaction initiated by a small amount of heat
What is an exothermic chemical reaction? - Correct Answers -a reaction that releases
more energy than it absorbs (ie. heat producing)
What are the four components of the fire tetrahedron? - Correct Answers -1. fuel
2. heat energy
3. oxygen
4. uninhibited chain reaction
Name the phases of a fire in order. - Correct Answers -pre-ignition, combustion,
smoldering
What is the pre-ignition phase? - Correct Answers -heat causes fuels to give off vapors
that can burn
What is the combustion phase? - Correct Answers -fuels vapors combine with oxygen in
a reaction that releases more heat
What is the smoldering phase? - Correct Answers -ash cover leads to slow, low-
temperature burning and prevents new fuels from igniting
What is a surface fire? - Correct Answers -a fire that occurs in grasses, pine needles,
and shrubs near to the ground
What enables surface fires and crown fires to burn easily and spread quickly? - Correct
Answers -their fuels have a large surface area to volume ratio (lots of exposed area to
react with oxygen)
What is a crown fire? - Correct Answers -a fire that occurs near and at the crowns of
trees (canopy) where fine branches and needles burn very quickly
, Which type of fire moves the fastest and burns the hottest? - Correct Answers -crown
fire
What starts most wildfires in the US? - Correct Answers -humans start 85% of all
wildfires
What natural phenomenon most often causes wildfires? - Correct Answers -lightning
Why do wildfires started by lightning tend to burn a larger area? - Correct Answers -they
often:
- occur in remote areas
- burn longer before being noticed
- are more difficult to fight
- are often left burn as a natural process
What factors influence to potential of a wildfire to spread? - Correct Answers -- type of
vegetation
- amount of rainfall (less rainfall => more spread)
- average temperature (higher temperature => dryer fuels => more spread)
- topography (steeper slopes => more spread)
- wind strength
What type of vegetation has most potential to burn and where is it found? - Correct
Answers -desert shrubs, between the west coat and mid-west
Does fire burn the fastest uphill or downhill? - Correct Answers -uphill
Where in the US has the greatest potential for wildfires to spread? - Correct Answers -
the deserts and mountains of the west
How fast can wildfires move (at top speed)? - Correct Answers -up to 80 mph
What is the largest wildfire in US history? - Correct Answers -the Great Fire of 1910:
burned 3 million acres in 2 days, killed 87 people including 78 firefighters, led to the
"fight all fires" policy of the National Forest Service
What was the original policy of the US forest service toward fighting wildfires? - Correct
Answers -fight them whenever and wherever they occur
What is the current policy of the US forest service toward fighting wildfires? - Correct
Answers -let them burn in "primitive" areas unless they endanger people or structures
What does the US forest service allow some wildfires to burn? - Correct Answers -to
prevent the build up of fuels over time; this allows natural fires to consume fuels which
prevents more catastrophic fires
