20 Wildland and Ground Fires

2 The Wildland Fire Triangle 20

3 Fuel Subsurface – under the ground Surface – up to 6’ above the ground Aerial – more than 6’ above the ground Fine - Includes dried vegetation such as twigs, leaves, needles, grass, moss, light brush and duff –Aids the ignition of heavier fuels Heavy - Includes large brush, heavy timber, stumps, branches, slash and dead timber on the ground –Do not spread a fire as rapidly as fine fuels –Can burn with a high intensity 20

5 Other Fuel Characteristics Size and Shape Compactness Continuity Volume/Quantity Moisture Content * Will determine rate of ignition, fire spread and intensity 20

6 Weather Moisture –Relative Humidity : Ratio of the amount of water vapor present in the air compared to the maximum amount the air can hold at a given temperature (Varies with the time of day and year) –Precipitation Wind Air Temperature 20 “The 10am Concept”

7 Topography Slope Aspect (N, E, S, W) Valleys Ridges Canyons Natural barriers eg. streams and lakes Manmade barriers eg. Highways * May increase or impede fire behaviour, rate of spread 20

8 Anatomy of a Wildland Fire 20

9 Anatomy of a Wildland Fire (2) Pocket –A dangerous place for fire fighters because it is an area of unburned fuel surrounded on three sides by fire Island –An unburned area surrounded by fire 20

10 Methods of Extinguishment Cooling the fuel Removing the fuel Smothering 20

11 Cooling a Wildland Fire Water is used to cool. –Backpack pump extinguishers –Portable pumps –Booster tanks from apparatus –Aircraft 20

12 Removing Fuel (1 of 2) Removal of fine fuels: –Fire broom –Steel fire rakes –McLeod fire tool Removal of heavier brush: –Adze –Pulaski axe –Hand saws, chainsaws –Tractors, plows, and bulldozers 20

13 Removing Fuel (2 of 2) Backfiring –When properly set can burn an area of vegetation in front of the fire, thereby creating an area devoid of vegetation 20

14 Removing the Oxygen Smothering –Most commonly used when overhauling the last remnants of a wildland fire –Earth is thrown on smoldering vegetation. –Not as useful during the more active phases of a fire Compressed air foam systems (CAFS) –Sticks to vegetation and structures in the fire’s path –When the heat of the fire reaches the foam, it absorbs the heat and breaks down the foam. –This cools the fuel. 20

15 Types of Attacks Direct attack Indirect attack 20

16 Direct Attacks Mounted by containing and extinguishing the fire at its burning edge Fire fighters might smother the fire with dirt, use hoses to apply water to cool the fire, or remove fuel. Dangerous to fire fighters because they must work in smoke and heat close to the fire 20

17 Indirect Attacks Most often used for large fires that are too dangerous to approach through a direct attack Mounted by building a fire line Can be mounted using hand tools or by using mechanized machinery Most appropriate when the topography is so rough that a direct attack is dangerous or impossible 20

18 Priorities of Attack IC must assess and evaluate the priorities for preserving lives and property before determining how to attack a wildland fire. 20

19 Safety in Wildland Firefighting Fighting wildland and ground fires is hazardous duty. Shares many of the hazards of structural firefighting plus additional hazards: –Driving, falls, smoke and fire, and falling trees 20

Hazards of Wildland Firefighting (1 of 2) Driving in rough terrain –Risk of rollover Working in rough terrain –Risk of falls Burns and smoke inhalation –Wear PPE –Use SCBA in conditions where needed 20

21 Falling trees –Trees of all sizes can fall with little warning. Electrical hazards –Wires that drop on vegetation may ignite. –Difficult to see at night and in smoky conditions 20 Hazards of Wildland Firefighting (2 of 2)

22 Personal Protective Equipment One-piece jumpsuit, or a coat, shirt, and trousers –Meet the requirements of NFPA 1977 –Garments should be constructed of a fire-resistant material like Nomex® –Wear an approved helmet with a protective shroud, eye protection, gloves, and protective footwear. –Respiratory protection Filter mask 20

23 Wildland Urban Interface The mixing of wildland with developed areas Wildland fires regularly ignite buildings and become structure fires. Fires in this zone present a significant life safety hazard. Many areas do not have adequate municipal water systems. 20

24 Fire Intensity Rankings (courtesy BC Forest Service 20 Rank 1 Smouldering ground or creeping surface fire Rank 2 Low vigor surface fire Rank 3 Moderately vigorous surface fire, “candling” Rank 4 Highly vigorous surface fire, torching (or passive crown fire) Rank 5 Extremely vigorous surface fire, or active crown fire Rank 6 Blow up/Conflagration, Extreme fire behaviour

25 The End 20