Fire Behaviour

Question 1

What are the 5 factors that influence fire behaviour?

Answer 1

1. Temperature
2. Wind
3. RH
   4.Percipitation
4. Atmospheric Stability

Question 2

List 3 considerations of Valley winds

Answer 2

Warm air goes up the slope in the day and down when things cool off, wind is slower going down usually
You can also get thermally induced winds from large bodies of water

Question 3

Why do wind speeds accelerate during peak burning? (p 20 of 46 in fire weather)

Question 4

Why does lower RH recovery occur in the north?

Answer 4

Because of the longer days, fire intensity picks up earlier in the day and

Question 5

What is the burning period?

Answer 5

Burning period referes to the the peak burn apart of the 24 hour durinal cycle usually between 1000-1800

Question 6

List visual indicators of a stable atmosphere

Answer 6

Cloud in layers, no verticle motion
Stratus type clouds
Smoke drifts apart after little rise
Poor visibility in lower areas due to haze and smoke
Fog layers
Steady Winds

Question 7

List visual indicators of an unstable atmosphere

Answer 7

Clouds or smoke grow vertically
Cumulus type clouds
upward/downward currents (turbulence)
Good visibility in lower areas
Dust whirls

Question 8

How can an unstable atmosphere impact fire behaviour?

Answer 8

-Erratic Winds
-Thunderstorm Development
-

Question 9

Review inversions and their importance pp. 25

Question 10

Review important cloud types? (Is this important? pp. 27)

Question 11

Name X important characteristics of a cold front

Answer 11

-They usually move from NW to SE
-They are assossiated often with a decrease in temperature
-They are assossiated with rain as the cold air pushes the warm, more humid air, into the clouds

Question 12

What is an upper trough and upper ridge and what is the significance of each? (34/46)

Question 13

What are the 5 main topographic influences on fire behaviour?

Answer 13

1. Slope
2. Elevation
3. Aspect
4. Shape (rolling etc)
5. Barriers (lakes and jazz)