20 Wildland Ground Fires 20 Objectives 1 of

20 Wildland Ground Fires

20 Objectives (1 of 3) • Define the terms wildland ground fires. • Define the types of wildland fires. • Define light fuels, heavy fuels, subsurface fuels, and aerial fuels. • Describe how weather factors and topography influence the growth of wildland fires.

20 Objectives (2 of 3) • Define the parts of wildland ground fires. • Describe how wildland ground fires can be suppressed. • List the hazards associated with wildland ground firefighting.

20 Objectives (3 of 3) • Describe the personal protective equipment needed for wildland firefighting. • Explain the problems created by the wildland-urban interface.

20 What are Wildland Fires? (1 of 3) • Defined by NFPA: – Unplanned and uncontrolled fires burning in vegetative fuel that sometimes includes structures. • Can consume grasslands, brush, and trees of all sizes • Incidence varies from season to season. • Referred to by different terminology

20 What are Wildland Fires? (2 of 3) • Ground cover fires burn loose debris on the surface of the ground. • Some fire departments respond to more wildland ground fires. • Many structural fire fighters are called on to extinguish wildland ground fires at some point.

20 What are Wildland Fires? • Large wildland fires are handled by specialized agencies. – Each state has an agency designated to coordinate wildland firefighting. – There are federal agencies that are responsible for coordinating firefighting activities at large incidents. (3 of 3)

20 Wildland Ground Fires and the Fire Triangle • Wildland ground fires require the same three elements as structural fires. – Fuel, oxygen, and heat • In wildland ground fires the conditions under which fuel, oxygen, and heat come together to produce a fire are different. • Weather conditions have a great impact on wildland fire behavior.

20 The Wildland Fire Triangle

20 Fuel (1 of 2) • Primary fuel is area vegetation. • Amount of fuel in an area ranges from sparse grass to heavy underbrush and large trees. • Some ignite readily and burn rapidly when dry.

20 Fuel (2 of 2) • Vegetative fuels can be located: – Under the ground (roots) – On the surface (grass and fallen leaves) – Above the ground (tree branches)

20 Fine Fuels • Includes dried vegetation such as twigs, leaves, needles, grass, moss, and light brush • Ground duff – Partly decomposed organic material on a forest floor • Main type of fuel in ground cover fires • Aid the ignition of heavier fuels

20 Heavy Fuels • Includes large brush, heavy timber, stumps, branches, and dead timber on the ground • Slash – Consists of the leftovers of a logging operation • Do not spread a fire as rapidly as fine fuels • Can burn with a high intensity

20 Subsurface Fuels • Located under the ground • Roots, moss, duff, and decomposed stumps • Fires involving subsurface fuels are hard to locate and extinguish.

20 Surface Fuels • Located close to the surface of the ground • Include grass, leaves, twigs, needles, small trees, and slash • Brush less than 6' above the ground • Sometimes called ground fuels • Involved in ground cover fires

20 Aerial Fuels • Also called canopy fuels • Located more than 6’ above the ground • Usually trees • Includes limbs, leaves, needles on limbs, and moss

20 Other Fuel Characteristics • Size and shape, compactness, continuity, volume, and moisture level determine how quickly the fuel ignites, how rapidly it burns, and how readily it spreads to other areas

20 Size and Shape of Fuel • Size and shape of a fuel influences how it burns. • Fine fuels burn more quickly than heavy fuels. • Requires less heat to reach their ignition temperature

20 Fuel Compactness • Influences the rate at which a fuel will burn • Air cannot circulate in and around fuels that are tightly compacted. • Subsurface fuels burn more slowly than aerial fuels.

20 Fuel Continuity • • Relative closeness of fuels Are close together or touch each other Fire spread from one area to the next Have a sufficient supply of air to support rapid combustion • Burn much more rapidly than fuels that are compact

20 Fuel Volume • Quantity of fuel available in a specific area • Amount of fuel in a given area influences the growth and intensity of the fire.

20 Fuel Moisture • Amount of moisture contained in a fuel • Influences the speed of ignition, the rate of spread, and the intensity of the fire. • Fuels with high moisture content will not ignite and burn as readily. • Fuel moisture varies with the amount of rain that has fallen.

20 Oxygen • Oxygen is needed. • Not usually an important variable in the ignition or spread of the fire. • Air movement influences the speed with which a fire moves. • Wind speeds the process of combustion and influences the direction the fire travels.

20 Heat • Sufficient heat must be applied to fuel in the presence of adequate oxygen to produce a fire. • Three categories of factors may ignite wildland ground fires: – Natural causes – Accidental causes – Intentional causes

20 Weather • Weather conditions have a large impact on the course of a wildland fire. – Moisture – Wind

20 Moisture (1 of 2) • 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 – A major factor in the behavior of wildland ground fires – Varies with the time of day and year

20 Moisture • Precipitation – Moisture falling from the sky helps to increase the relative humidity. – Absorbed by plants – When there is adequate precipitation, fire risk is lower. (2 of 2)

20 Wind • Has the ability to move a fire at great speed • Effect of wind on a wildland ground fire is similar to fanning a fire to help it burn more rapidly

20 Topography (1 of 2) • Changes of elevation in the land the position of natural and manmade features • Has a great impact on the fire behavior • When the elevation rises in the direction the fire is traveling, the fire heat ignites a greater quantity of fuel and increases the speed of fire spread.

20 Topography (2 of 2) • Natural barriers, such as streams and lakes, may help contain fires. • Manmade barriers such as highways also make it easier to contain a fire.

20 Anatomy of a Wildland Fire • Area of origin – Location where fires begin • Head of the fire – Main or running edge of a fire – Part of the fire that spreads with the greatest speed (1 of 4)

20 Anatomy of a Wildland Fire (2 of 4) • Heel of the fire or the rear of the fire – Side opposite the head of the fire, often close to the area of origin • Finger – Narrow point of fire caused by a shift in wind or a change in topography – Can grow and produce a secondary direction of travel for the fire

20 Anatomy of a Wildland Fire (3 of 4) • 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 Anatomy of a Wildland Fire (4 of 4) • Spot fire – New fire that starts outside areas of the main fire • Green – Area of unburned fuels • Black – Areas that have already been burned

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

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

20 Removing Fuel • Removal of fine fuels can be accomplished with: – Fire broom – Steel fire rakes – Mc. Leod fire tool (1 of 2)

20 Removing Fuel (2 of 2) • Sometimes saws are used to remove heavy brush and trees from the fire. – Hand saws to gasoline powered chainsaws – Tractors, plows, and bulldozers • Backfiring – When properly set can burn an area of vegetation in front of the fire, thereby creating an area devoid of vegetation

20 Removing the Oxygen (1 of 2) • Smothering – Most commonly used when overhauling the last remnants of a wildland ground fire – Earth is often thrown on smoldering vegetation to prevent flare-ups. – Not as useful during the more active phases of a fire

20 Removing the Oxygen (2 of 2) • Compressed air foam systems (CAFS) – Combines foam concentrate, water, and compressed air to produce a foam – 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 Types of Attacks • Direct attack – Pincer attack – Flanking attack • Indirect attack

20 Direct Attacks (1 of 5) • 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 Direct Attacks (2 of 5) • Pincer Attack – Requires two teams of fire fighters. – Team one mounts a direct attack along the left flank near the point of origin. – Team two mounts a direct attack along the right flank near the point of origin. – This allows the fire to be “pinched” between the two teams

20 Direct Attacks (3 of 5)

20 Direct Attacks (4 of 5) • Flanking Attack – Only requires one team – Attack is made on either flank which is based on the flank with the greatest risk.

20 Direct Attacks (5 of 5)

20 Indirect Attacks • Used for large fires that are too dangerous to approach through a direct attack • Mounted by building a fire line • Use hand tools or machinery • Most appropriate when the topography is so rough that a direct attack is dangerous or impossible

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

20 Fire Apparatus Used for Wildland Fires (1 of 2) • Structural Fire Apparatus – Do not have pump and roll capabilities – Do not possess offroad capabilities

20 Fire Apparatus Used for Wildland Fires (2 of 2) • Wildland Fire Apparatus – Range from small pick-up trucks and jeeps to large all-wheel drive trucks • Small apparatus usually carry 200– 300 gallons • Larger apparatus on large truck chassis • Tanker are designed to move water for the smaller units. • Plows and bulldozers

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

20 Personal Protective Equipment • Jumpsuit, or a coat, shirt, and trousers – Meet the requirements of NFPA 1977 – Garments should be constructed of a fireresistant material like Nomex® – Respiratory protection

20 Fire Shelters • Lifesaving piece of equipment • Designed to reflect about 95% of a fire’s radiant heat for a short period of time • Fire fighters use their fire shelters when unable to reach safety in time.

20 Wildland Urban Interface • The mixing of wildland with developed areas • Wildland fires regularly ignite buildings and become structure fires. (1 of 2)

20 Wildland Urban Interface (2 of 2) • Wildland urban interface – Area where undeveloped land with vegetative fuels is mixed with manmade structures • Fires in this zone present a significant life safety hazard. • Many areas do not have adequate municipal water systems.

20 Summary (1 of 2) • Wildland fires are unplanned and uncontrolled fires burning in vegetative fuel that sometimes includes structures. • Fire fighters need to understand the factors that cause fire ignition and affect the growth and spread of wildland fires.

20 Summary (2 of 2) • Growth of the fire is influenced by weather factors and by the topography of the land. • Assess and evaluate the priorities for preserving lives and property. • The wildland urban interface creates a massive problem for fire departments.