Wildland and Ground Fires 20 Wildland and Ground Fires

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

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

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

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

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 and ground fires. Many structural fire fighters are called on to extinguish wildland and ground fires at some point.

What are Wildland Fires? (3 of 3) 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.

Wildland and Ground Fires and the Fire Triangle Wildland and ground fires require the same three elements as structural fires. Fuel, oxygen, and heat In wildland and 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.

The Wildland Fire Triangle

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.

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)

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

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

Subsurface Fuels Located under the ground Roots, moss, duff, and decomposed stumps Fires involving subsurface fuels are hard to locate and extinguish. Courtesy of Bob McMillan/FEMA.

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

Aerial Fuels Also called canopy fuels Located more than 6’ above the ground Usually trees Includes limbs, leaves, needles on limbs, and moss Courtesy of Andrea Booher/FEMA.

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

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 Courtesy of NPS.

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.

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

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.

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.

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.

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 and ground fires: Natural causes Accidental causes Intentional causes

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

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 and ground fires Varies with the time of day and year

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

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

Topography (1 of 2) Changes of elevation in the land and 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.

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.

Anatomy of a Wildland Fire (1 of 4) 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

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

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

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

Methods of Extinguishment Cooling the fuel Removing the fuel Smothering

Cooling a Wildland Fire Water is used to cool. Backpack pump extinguishers Booster tanks from apparatus Aircraft © Doug Dreyer/AP Photos.

Removing Fuel (1 of 2) Removal of fine fuels can be accomplished with: Fire broom Steel fire rakes McLeod fire tool

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

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

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.

Types of Attacks Direct attack Indirect attack Pincer attack Flanking attack Indirect attack

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

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

Direct Attacks (3 of 5)

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.

Direct Attacks (5 of 5)

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

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

Fire Apparatus Used for Wildland Fires (1 of 2) Structural Fire Apparatus Do not have pump and roll capabilities Do not possess off-road capabilities © Steven Townsend/Code 3 Images.

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

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

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

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

Personal Protective Equipment Jumpsuit, or a coat, shirt, and trousers Meet the requirements of NFPA 1977 Garments should be constructed of a fire-resistant material like Nomex® Respiratory protection © Karen Wattenmaker Photography.

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. Courtesy of Anchor Industries, Inc.

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

Wildland Urban Interface (2 of 2) 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.

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.

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.