|
|
|
|
Wildland fire suppression
|
| |
|
| |
Wildfire suppression refers to the firefighting tactics used to suppress wildfires. Firefighting efforts in wildland areas requires different techniques, equipment, and training from the more familiar structure fire fighting found in populated areas. Working in conjunction with specially designed firefighting aircraft, these wildfire-trained crews suppress flames, construct firelines, and extinguish flames and areas of heat to protect resources and natural wilderness.
Discussion
Ask a question about 'Wildland fire suppression' Start a new discussion about 'Wildland fire suppression' Answer questions from other users |
Encyclopedia
Wildfire suppression refers to the firefighting tactics used to suppress wildfires. Firefighting efforts in wildland areas requires different techniques, equipment, and training from the more familiar structure fire fighting found in populated areas. Working in conjunction with specially designed firefighting aircraft, these wildfire-trained crews suppress flames, construct firelines, and extinguish flames and areas of heat to protect resources and natural wilderness. Wildfire suppression also addresses the issues of the wildland-urban interface, where populated areas border with wildland areas.
History
Wildland fire use, or the concept of allowing fire, either naturally-occurring or man-made, as a tool to accomplish a goal, had its origin when humans first gained the ability to suppress fires. Some fires were suppressed and others were allowed to burn based on human values and objectives. Native Americans and Euro-American settlers fought fires that threatened their villages and settlements. Others were left to burn unabated. Even with the advent of advanced fire suppression capabilities during the late 1880s, control efforts were focused on areas of human development. Fires in remote areas were largely ignored.
United States
Within the United States, Yellowstone National Park was established in 1872 as the world’s first national park. For the next several years, administration of the park languished until 1886 when the U. S. Army was assigned the responsibility for its protection. Upon its arrival in the park, the Army found numerous fires burning in developed areas as well as in areas where it was not reasonable to control them. The commanding officer decided that human-caused fires along roads posed the biggest threat and that the Army would concentrate its suppression efforts on the control of those fires. There were not enough soldiers to fight all of the fires. Thus, came the first conscious decision by a manager of federal land to allow some fires to burn while others were controlled. The policy of fire suppression was also applied to Sequoia, General Grant, and Yosemite national parks when they were established in 1890, and Army patrols were initiated to guard against fires, livestock trespass, and illegal logging.
The U.S. Forest Service was established in 1905. It became the primary task of the Forest Service to suppress all fires on the forest reserves it administered. In 1916, the National Park Service was established and took over management from the Army. Following the Forest Service approach, fire suppression became the only fire policy and remained in the national parks for the next five decades. Some foresters questioned the economic logic of such suppression efforts. However, the extensive fires of 1910 solidified the Forest Service as the premier fire control organization and fire suppression remained the only fire policy for all federal land management agencies until the late 1960s.
Complete fire suppression was the objective, even though these early efforts were less than successful until the advent of vehicles, equipment, and roads (see Fire trail) during the 1940s. Some managers allowed low intensity fires to spread in remote areas unless they threatened valuable resources or facilities, by 1934 a policy of extinguishing all fires by 10:00 AM of the next burning period was implemented. This resulted in the buildup of fuels in some ecosystems such as Ponderosa Pine and Douglas Fir forests.
The policy began to be questioned in the 1960s, when it was realized that no new Giant Sequoia had been grown in the forests of California, because fire is an essential part of their life cycle. In 1962, the Secretary of the Interior asked a committee to look into wildlife management problems in the national parks. This committee, named after its chair, Dr. A. Starker Leopold, did not confine its report to wildlife, but took the broader ecological view that parks should be managed as ecosystems. The passage of the 1964 Wilderness Act encouraged the allowance of natural processes to occur, including fire. Afterwards, the National Park Service changed its policy in 1968 to recognize fire as an ecological process. Fires were to be allowed to run their courses as long as they could be contained within fire management units and accomplished approved management objectives. Several parks established fire use programs, and policies were gradually changed from fire control to fire management. The Forest Service enacted similar measures in 1974 by changing its policy from fire control to fire management, allowing lightning fires to burn in wilderness areas. This included both naturally caused fire and intentional prescribed fire. In 1978, the Forest Service abandoned the 10:00 AM policy in favor of a new policy that encouraged the use of wildland fire by prescription.
Three events between 1978 and 1988 precipitated a major fire use policy review in 1989: the Ouzel fire in Rocky Mountain National Park, the Yellowstone fires of 1988 in and around Yellowstone National Park, and the Canyon Creek fire in the Bob Marshall Wilderness on the Lewis and Clark National Forest. In all three cases, monitored fires burned until they threatened developed areas. While the Yellowstone fires of 1988 were caused by escaped fires from controlled burns, later investigations proved the fire use policy was appropriate, though needing strengthening and improvement.
The Secretaries of Agriculture and the Interior convened a fire policy review team to evaluate the National Park Service and Forest Service wilderness fire policies. The team reaffirmed the fundamental importance of fire’s natural role but recommended that fire management plans be strengthened by establishing clear decision criteria and accountability, and that interagency cooperation be improved. Wildland fire use programs restarted slowly after the 1989 review. Eventually the Forest Service and National Park Service programs began to grow as the number of fires and area burned increased.
The South Canyon Fire became controversial. It was ignited by lightning in a fire exclusion zone July 2, 1994. Suppression action was taken on the wildfire within two days of its start, but a blow-up two days later killed 14 fire fighters. An interagency team was formed and issued their report in August. They cited several direct and contributory causes of the fatalities including fire behavior, personnel profiles, and incident management procedures. The South Canyon incident led to the first comprehensive review and update of federal wildland fire policy in decades. The report reiterated that the first priority of all federal wildland fire programs was firefighter and public safety. With regard to prescribed fires and prescribed natural fires, the report stated that, “Wildland fire will be used to protect, maintain, and enhance resources and, as nearly as possible, be allowed to function in its natural ecological role.” In 1998, a new procedures guide used the term “wildland fire use” to describe what had previously been prescribed natural fires. By the end of the decade, a 1995 policy had reinvigorated “wildland fire use” programs and given managers the support they needed to enable the programs to continue to grow and mature.
Fire management benefits began to appear, such as the 2000 Hash Rock fire which burned almost all of the Mill Creek Wilderness on the Ochoco National Forest in Oregon before it was suppressed. When the wildfire reached the 1996 Mill Creek fire, which had been managed under the wildland fire use program, it went out. Use of fire presently varies in various federal agencies, partially due to differing influences such as land proximity to urban areas.
Canada
The fire exclusion policies of Canadian wildfire management agencies began around the 1900s, focusing on aggressive attacks to limit areas burned by wildfires. Current efforts recognize fire as a natural component in wildland systems.
Australia
Wildland fire has played a major role in Australia due to arid conditions similar to those in the western U.S. The preferred term for wildfire in Australia is bushfire. Notable fire services tasked with wildfire suppression include:
Objectives
Safety
Protection of human life, both firefighters and civilians, is first priority. When arriving on a scene a fire crew will establish a safety zone(s), escape routes, verify communication is in place and designate lookouts (known in the U.S. by the acronym LCES, for lookouts, communications, escape routes, safety zones). This allows the firefighters to engage a fire with options for a retreat should their current situation become unsafe. Although other safety zones should be designated, areas already burned generally provide a safe refuge from fire provided they have cooled sufficiently, are accessible, and have burned enough fuels so as to not reignite. Briefings may be done to inform new fire resources of hazards and other pertinent information.
A great emphasis is placed on safety and preventing entrapment, or a situation where escape from the fire is impossible. Prevention of this situation is reinforced with a list of 10 fire orders and 18 watch out situations for firefighters to be aware of, which warn of potentially dangerous situations. As a last resort, all wild land firefighters carry a fire shelter. In this unescapable situation, the shelter will provide limited protection from radiant and convective heat, as well as superheated air. Entrapment within a fire shelter is called a burnover.
Hazards beyond the fire are posed as well. A very small sample of these include: unstable hazard trees, animals, electrical cables, unexploded ordinance, hazardous materials, rolling and falling debris, and lightening.
Resource protection
Other resources are ranked according to importance and/or value. These include but are not limited to human health and safety, construction cost, ecological impacts, social and legal consequences and the costs of protection. Defendability is also considered, as more effort will be expended on saving a house with a tile roof than one with a wooden-shake roof, for example.
Management
Managing any number of resources over varying-size areas in often very rugged terrain is extremely challenging. An incident commander (IC) is charged with overall command of an incident. In the U.S., the Incident Command System designates this as being the first on scene providing he has sufficient training. The size of the fire, measured in acres or chains, will later dictate the class-level of IC required. Incident management teams aid on larger fire incidents to meet more complex priorities and objectives of the incident commander. It provides support staff to handle duties such as communication, fire behavior modeling, and map- and photo-interpretation. Again in the U.S., management coordination between fires is primarily done by the National Interagency Fire Center (NIFC)
| U.S. Fire Size Class | |
| A | B | C | D | E | F | G | | 0-1/4 acre | 1/4-10 acres | 10-99 acres | 100-299 acres | 300-999 acres | 1000-4999 acres | 5000+ |
Specific agencies and different incident management teams may include a number of different individuals with various responsibilities and varying titles. A fire information officer (IFO) generally provides fire-related information to the public for example. Branch chiefs and division chiefs serve as management on branches and divisions, respectively, as the need for these divisions arise. Investigators may be called to ascertain the fire's cause. Prevention officers such as forest rangers may patrol their jurisdictional areas to teach fire prevention and prevent some human-caused fires from happening to begin with.
Communication
Information may be communicated on fires in many forms. Radios, vocals, visual signals such as flagging and mirrors, literature such as an IAP or incident action plan, whistles and mobile touch-screen computer terminals are examples some examples
The USFS Visual Signal Code system provides a symbols used to communicate air-to-ground, while aircraft may use wing tilting, motor gunning or circling to communicate air-to-ground.
Tactics
Operating in the U.S. within the context of fire use), firefighters may only suppress fire that has become uncontrollable. Conversely, fires or portions of a fire that have previously been engaged by firefighters may, by management's decision, may be treated as fire use situation and be left to burn unfettered.
All fire suppression activities are based from an anchor point (such as lake, rock slide, road or other natural or artificial fire break). From an anchor point firefighters can work to contain a wild land fire without the fire outflanking them.
Large fires often become extended campaigns. ICPs or incident posts are temporary fire camps and are constructed to provide food, showers, and rest to fire crews.
Weather conditions and fuel conditions are large factors in the decisions made on a fire. Within the U.S., the Energy Release Component (ERC) is a scale relating fuel energy potential to area. The Burning Index (BI) relates flame length to fire spread speed and temperature. The Haines Index (HI) tracks stability and humidity of air over a fire. The Keeth-Byrum Dought Index relates fuels to how quickly they could ignite and to what percentage they should burn. The Lightening Activity Level (LAL) ranks lightening potential into six classes.
Fuel models are specific fuel designations determined by energy burning potential. Placed into 13 classes, they range from "short grass" (model 1) to "logging slash" (model 13). Low-numbered models burn at lower intensities than those at the higher end.
Direct attack
Direct attack is any treatment applied directly to burning fuel such as wetting, smothering, or chemically quenching the fire or by physically separating the burning from unburned fuel. This includes the work of fire engines, fire crews, and aircraft applying water or fire retardant directly to the burning fuel. For most agencies, the objective is to construct a fireline around all fire meant to be suppressed.
Indirect attack
Preparatory suppression tactics used a distance away from the oncoming fire are considered indirect. Firelines may be built in this manner as well. Fuel reduction, indirect firelines, contingency firelines, backburning and wetting unburnt fuels are examples. This method may allow for more effective planning. It may allow for more ideally placed firelines in lighter fuels using natural barriers to fire and for safer firefighter working conditions in less smoke filled and cooler areas. However, it may also allow for more burned acreage, larger hotter fires, and the possibility of wasted time constructing unused firelines.
Attempts to control wildfires may also include by controlling the area that it can spread to by creating control lines: boundaries that contain no combustible material. These may be constructed by physically removing combustible material with tools and equipment, or portions may be naturally occuring. Lines may also be created by creating small, low-intensity fires using driptorches or flares. The resultant fires are extinguished by firefighters or, ideally, directed in such a way that they meet the main fire front, at which point both fires run out of flammable material and are thus extinguished. Additionally, the use of long-term fire retardants, fire-fighting foams, and superabsorbent polymer gels may be used. Such compounds reduce the flammability of materials by either blocking the fire physically or by initiating a chemical reaction that stops the fire.
Unfortunately, any method can fail in the face of erratic or high-intensity winds and changing weather. Changing winds may cause fires to change direction and miss control lines. High-intensity winds may cause jumping or spotting as burning embers are carried through the air over a fireline. Burning trees may fall and burning materials may roll across the line, effectively negating the barrier.
Mop-up
The threat of wildfires does not cease after the flames have passed, as smoldering heavy fuels may continue to burn unnoticed for days after flaming. It is during this phase that the exterior of or the complete burn area of a fire has cooled so as to not reignite another fire.
Rehabilitation
Constructed firelines, breaks, safety zones and other items may damage soil systems, encouraging erosion from surface run-off and gully formation. The loss of plant life from the fire also contributes to erosion. Construction of waterbars, the addition of plants and debris to exposed soils and other measures help to reduce this.
Fires on the wildland-urban interface
Expansive urbanization and other human activity in areas adjacent to wildlands is a primary reason for the catastrophic structural losses experienced in wildfires. Continued development of wildland-urban interface firefighting measures and the rebuilding of structures destroyed by fires has been met with criticism. Communities such as Sydney and Melbourne in Australia have been built within highly flammable forest fuels. The city of Cape Town, South Africa lies on the fringe of the Table Mountain National Park. In the western United States from the 1990s to 2007, over 8.5 million new homes were constructed on the wildland-urban interface.
Fuel buildup can result in costly, devastating fires as more new houses and ranches are built adjacent to wilderness areas. However, the population growth in these fringe areas discourages the use of current fuel management techniques. Smoke from fires is an irritant and a pollutant. Attempts to thin out the fuel load may be met with opposition due to the desirability of forested areas. Wildland goals may be further resisted because of endangered species protections and habitat preservation. The ecological benefit of fire is often overridden by the economic benefits of protecting structures and lives. Additionally, federal policies that cover wildland areas usually differ from local and state policies that govern urban lands.
In North America, the belief that fire suppression has substantially reduced the average annual area burned is widely held by resource managers and is often thought to be self-evident. However, this belief has been the focus of vocal debate in the scientific literature.
Equipment and personnel
Personnel
PPE or personal protective equipment is generally standardized for a certain type of team or crew. Smokejumpers for example require more protective equipment because of their method of delivery into the fire. Ordinarily, all firefighters regardless of assignment require durable fire recommended boots, gloves, Nomex pants and shirt, a hard hat, water and a fire shelter.
In the U.S., a firefighter's credentials and level of training is shown on their red card. For example, a Sawyer will have a feller rating on their red card designating the capacity size tree they have been trained to fell. A firefighter trained as an EMT may have this certification on their card. Classes under the National Wildfire Coordinating Group (NWCG) and management qualification standards under the Interagency Fire Program Management (IFPM) are generally shown as well.
Hand crews
Typically, wildland firefighting organizations will use large crews of 20 or more people who travel in vehicles to the fire incident. Although these crews can vary above or below 20 firefighters, they are generally called twenty man crews. The designations of these crews in the U.S., defined in large portion by training, are as follows:
- Type I Interagency Hotshot crew
- Type I Crew
- Type II Initial Attack (IA) Crew
- Type II Crew
- Type III Crew
Some personnel are organized into fast attack teams typically consisting of five to eight personnel. Similar to the larger crews, they travel by vehicle.
Smokejumpers
Smokejumpers are highly-skilled firefighters specially trained in wildfire suppression tactics. They
parachute into remote areas from aircraft to combat wildfires and are equipped to work in remote areas for extended periods of time with little logistical support.
Helitack
The use of helicopter-delivered fire resources varies by agency. Often, helitack crews perform duties similar to other initial attack crews. Two or three firefighters will be dispatched to a newly-reported fire. Helitack crews are usually used for initial attack on fires that are difficult for other firefighters to access, or on extended fires that require aerial support in the form of water drops, cargo delivery, crew shuttling, or reconnaissance. A typical initial attack response by a helitack crew involves flying to the fire via helicopter and spending one to three days (although sometimes much longer) putting the fire out before hiking to the nearest road for pickup.
Rappellers
A highly effective way to fight wilderness fire when no roads are nearby is to have wildland firefighters rappel from a helicopter. These firefighters then take suppressive action on the fire or clear a safe landing zone to receive additional firefighters if the fire is too large. Rappellers usually carry 30 pounds of personal gear plus up to 300 pounds of fire gear which is lowered down to them from their helicopter. Rappelling heights can range from 30 feet (in tall, continuous brush) to 250 feet (in timber). When suppression is complete on rappel fires, ground transport is typically arranged to pick up the firefighters at the nearest road. These crews carry chainsaws, hand tools, radios, and can even have 75 gallon water bags, known as blivets, flown in to help fight the fire. When not rappelling, the crew works as a helitack crew and can fly or hike to any regular fire.
Vehicles
Engines
Crew transport
Tenders
When water is required to refill a fire engine, water delivery is vital. The typical water tender carries 1200 gallons of water to support fire engines. In addition to supplying fire engines directly, tenders may fill water reservoirs for bucket-dropping helicopters when a lake or reservoir is not nearby.
Heavy equipment
Heavy equipment's primary function of wildfire suppression is through the application of heavy construction style equipment to move large amounts or earth or remove vegetation. Fuel breaks, safety zones, firelines and access to areas that maybe previously were inaccessible may be made. Bulldozers and tractor plows are examples.
Air suppression
In addition to aircraft being used for deploying ground personnel, firefighting groups may utilize helicopters and fixed-wing airplanes specially equipped for use in aerial firefighting to douse areas that are inaccessible to vehicles with water and/or flame retardant chemicals.
Fixed-wing airplanes
Rotary-wing aircraft
- Helicopters (helitack & rappel)
- Helicopter (water delivery)
Hand tools
A number of tools are used in wildland firefighting. Some examples include:
See also
Citations
External links
|
| |
|
|
