 | This article includes a list of general references, but it lacks sufficient corresponding inline citations .(March 2024) |
The Ignition Component (IC) is a number which relates the probability that a fire will result if a firebrand is introduced into a fine fuel complex. It is a component of the National Fire Danger Rating System (NFDRS).
The ignition component can range from 0 when conditions are cool and damp, to 100 on days when the weather is dry and windy. Theoretically, on a day when the ignition component value is 0 a single firebrand will not start a Wildland fire requiring suppression action. A value of 50, there is a 50% probability a single firebrand could start a wildfire requiring suppression action. And when the value is 100, there is a 100% probability a wildfire will result from a single firebrand that will require suppression action to stop the fire from spreading in wildland fuels. In relation to fire danger, IC of 100 means that every firebrand will cause an actionable fire if it contacts receptive fuel, extreme. Likewise, IC of 0 no firebrand would cause an actionable fire under those conditions, low fire danger. [1]
Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. At a certain point in the combustion reaction, called the ignition point, flames are produced. The flame is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce plasma. Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity will be different.
A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire, desert fire, grass fire, hill fire, peat fire, prairie fire, vegetation fire, or veld fire. Some natural forest ecosystems depend on wildfire. Wildfires are distinct from beneficial human usage of wildland fire, called controlled or prescribed burning, although controlled burns can turn into wildfires. Modern forest management often engages in prescribed burns to mitigate risk and promote natural forest cycles.
A controlled or prescribed (Rx) burn, which can include hazard reduction burning, backfire, swailing or a burn-off, is a fire set intentionally for purposes of forest management, fire suppression, farming, prairie restoration or greenhouse gas abatement. A controlled burn may also refer to the intentional burning of slash and fuels through burn piles. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters.
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires.
Firefighting jargon includes a diverse lexicon of both common and idiosyncratic terms. One problem that exists in trying to create a list such as this is that much of the terminology used by a particular department is specifically defined in their particular standing operating procedures, such that two departments may have completely different terms for the same thing. For example, depending on whom one asks, a safety team may be referred to as a standby, a RIT or RIG or RIC, or a FAST. Furthermore, a department may change a definition within its SOP, such that one year it may be RIT, and the next RIG or RIC.
This glossary of wildfire terms is a list of definitions of terms and concepts relevant to wildfires and wildland firefighting. Except where noted, terms have largely been sourced from a 1998 Fireline Handbook transcribed for a Conflict 21 counter-terrorism studies website by the Air National Guard.
Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts depend on many factors such as the available fuel, the local atmospheric conditions, the features of the terrain, and the size of the wildfire. Because of this wildfire suppression in wild land areas usually requires different techniques, equipment, and training from the more familiar structure fire fighting found in populated areas. Working in conjunction with specially designed aerial firefighting aircraft, fire engines, tools, firefighting foams, fire retardants, and using various firefighting techniques, wildfire-trained crews work to suppress flames, construct fire lines, and extinguish flames and areas of heat in order to protect resources and natural wilderness. Wildfire suppression also addresses the issues of the wildland–urban interface, where populated areas border with wild land areas.
The Yellowstone fires of 1988 collectively formed the largest wildfire in the recorded history of Yellowstone National Park in the United States. Starting as many smaller individual fires, the flames quickly spread out of control due to drought conditions and increasing winds, combining into several large conflagrations which burned for several months. The fires almost destroyed two major visitor destinations and, on September 8, 1988, the entire park was closed to all non-emergency personnel for the first time in its history. Only the arrival of cool and moist weather in the late autumn brought the fires to an end. A total of 793,880 acres (3,213 km2), or 36 percent of the park, burned at varying levels of severity.
National Fire Danger Rating System (NFDRS) is used in the United States to provide a measure of the relative seriousness of burning conditions and threat of wildfires.
A dry thunderstorm is a thunderstorm that produces thunder and lightning, but where most of its precipitation evaporates before reaching the ground. Dry lightning refers to lightning strikes occurring in this situation. Both are so common in the American West that they are sometimes used interchangeably.
Wildfire modeling is concerned with numerical simulation of wildfires to comprehend and predict fire behavior. Wildfire modeling aims to aid wildfire suppression, increase the safety of firefighters and the public, and minimize damage. Wildfire modeling can also aid in protecting ecosystems, watersheds, and air quality.
Wildfire suppression in the United States has had a long and varied history. For most of the 20th century, any form of wildland fire, whether it was naturally caused or otherwise, was quickly suppressed for fear of uncontrollable and destructive conflagrations such as the Peshtigo Fire in 1871 and the Great Fire of 1910. In the 1960s, policies governing wildfire suppression changed due to ecological studies that recognized fire as a natural process necessary for new growth. Today, policies advocating complete fire suppression have been exchanged for those who encourage wildland fire use, or the allowing of fire to act as a tool, such as the case with controlled burns.
The wildland–urban interface (WUI) is a zone of transition between wilderness and land developed by human activity – an area where a built environment meets or intermingles with a natural environment. Human settlements in the WUI are at a greater risk of catastrophic wildfire.
Wildfire suppression equipment and personnel is part of the science of fire fighting focusing on the use of specialized equipment, training and tactics to effectively control, surround and eventually extinguish a natural cover fire. There are several specially designed tools that through their function and user training, perform specialized tasks that are specific to natural cover firefighting. This is used together in conjunction with the general understanding of the behavior of fire to form a viable plan of attack.
A fire-adapted community is defined by the United States Forest Service as "a knowledgeable and engaged community in which the awareness and actions of residents regarding infrastructure, buildings, landscaping, and the surrounding ecosystem lessens the need for extensive protection actions and enables the community to safely accept fire as a part of the surrounding landscape."
Wildfires are outdoor fires that occur in the wilderness or other vast spaces. Other common names associated with wildfires are brushfire and forest fire. Since wildfires can occur anywhere on the planet, except for Antarctica, they pose a threat to civilizations and wildlife alike. In terms of emergency management, wildfires can be particularly devastating. Given their ability to destroy large areas of entire ecosystems, there must be a contingency plan in effect to be as prepared as possible in case of a wildfire and to be adequately prepared to handle the aftermath of one as well.
Wildfires can happen in many places in the United States, especially during droughts, but are most common in the Western United States and Florida. They may be triggered naturally, most commonly by lightning, or by human activity like unextinguished smoking materials, faulty electrical equipment, overheating automobiles, or arson.
Pyrogeography is the study of the past, present, and projected distribution of wildfire. Wildland fire occurs under certain conditions of climate, vegetation, topography, and sources of ignition, such that it has its own biogeography, or pattern in space and time. The earliest published evidence of the term appears to be in the mid-1990s, and the meaning was primarily related to mapping fires The current understanding of pyrogeography emerged in the 2000s as a combination of biogeography and fire ecology, facilitated by the availability of global-scale datasets of fire occurrence, vegetation cover, and climate. Pyrogeography has also been placed at the juncture of biology, the geophysical environment, and society and cultural influences on fire.
Samuel L. Manzello is a technical advisor at Reax Engineering and visiting professor Tohoku University (Japan). He has worked on microgravity droplet combustion, droplet-surface interaction, soot formation in well-stirred reactor/plug flow reactor, fire-structure interaction, and structure vulnerabilities in wildland-urban interface (WUI) fires.