Fire Behaviour Flashcards
What does the a fire need?
Fuel
Oxygen
Heat
What are the 3 methods of heat transfer?
Radiation
Convection
Conduction
How do you deploy a fire shelter?
Feet pointed towards the fire Dug into dirt, never rocks or sand Behind natural wind breaks All surrounding fuel sources removed Grouped together
How long does it take grass to absorb water or dry?
1 hour
What are the 6 characteristics of fuel sources?
- Fuel type
- Fuel moisture
- Size and shape
- Fuel loading
- Horizontal continuity
- Vertical arrangement
Why does brush and shrubs burn more intensely than grass?
Oils in the plant
What are widow makers and snags?
Widow makers are standing dead trees and snags are limbs that can fall from them and injure
What is Fuel Load
The amount of available combustible fuel in an area.
What are Uniform fuels?
Fuels distributed in a continuous network that allows fires to spread faster and further.
What are Patchy fuels?
Fuel sources that are spread out or with barriers between them.
What are Ground fuels?
All combustible material lying beneath the surface including duff, tree roots, rotting logs, peat and other organic material.
What is Duff and Slash?
Duff is dry pine needles, cones and leaves
Slash are sticks and branches laying on the ground
What are Ladder fuels?
Any fuels that provide a connection between the surface and upper canopy such as vines.
what are Aerial fuels?
All fuel sources located up in the canopy.
What is Time Lag?
The rate at which fuel gains / loses moisture due to: RH Size of fuels Precipitation Temperature Wind
What is the Dead fuel time lag in relation to size?
0” - 1/4” is 1 hour
1/4” - 1” is 10 hours
1” - 3” is 100 hours
3” - 8” is 1000 hours
What are the 4 factors of Weather?
Temperature
Wind
RH
Precipitation
What are the 3 speeds of a surface fire?
Shouldering, creeping and running
What does Spotting mean?
Embers and sparks carried by the wind or convection starting new “spot fires”
What does Crowning mean?
Fire advancing from tops to tops of trees or shrubs more or less independent of the surface
What is a Flare up?
A sudden acceleration of a fire that quickly burns out.
What is a Firewhirl?
A spinning moving column of ascending air rising within a vortex and carrying aloft smoke, debris and flames.
What are the 5 Factors of Topography?
- Aspect
- Slopes
- Shape of country
- Elevation
- Barriers
