| Weather | Topography | Fuel |
|---|---|---|
| Wind | Slope | Quantity |
| Temperature | Aspect (direction) | Continuity |
| Humidity | Position (on the terrain) | Size |
| Drought | Features (draws, saddles) | Arrangement |
| Season | Elevation | Moisture content |
Understanding Fire and Fire Behavior.
Ecological Restoration Institute, Northern Arizona University (PDF: 290KB).
The terms below have been compiled by Boulder County Wildfire Mitigation Services and include most of the terms used in this plan. If you can't find it here, refer to the USFS glossary found at the Rocky Mountain Region's National Fire Plan website, or the even more exhaustive glossary that can be downloaded from the National Wildfire Coordinating Group (PDF: 938KB).
- Canopy Closure - The distance between the tree tops if one were to look straight up. If the canopy closure is very dense, then the spacing is very tight with very little sunlight able to pass through.
- Cistern - Water storage vessel.
- Defensible Space - A designated area around your home that is intentionally maintained so as to be free of any features that would tend to increase the risk of damage from wildfire.
- Dry Hydrant - A non-pressurized pipe system permanently installed in existing lakes, ponds, and streams that provides means of suction supply of water to the tank truck. The dry hydrant system gives the trucks access to the ponds and streams from the main road.
- Fire Resistant Materials/Construction - Construction materials designed to resist the spread of fire. For detailed descriptions see the Uniform Building Code.
- Fuel Break - An area, strategically located for fighting anticipated fires, where the native vegetation has been permanently modified or replaced so that fires burning into it can be more easily controlled. Fuel breaks divide fire-prone areas into smaller areas for easier fire control and to provide access for fire fighting.
- Ladder Fuels - Materials which allow fire to move vertically from the ground up to the tops of trees (e.g., dead fuels to lower branches to other intermediate trees and shrubs to the upper tree canopies).
- Mitigation - To make or become less severe; an effort at reducing or eliminating the impacts of injury or damage from a hazard or disaster.
- Noncombustible Materials - A material which, in the form in which it is used, is either one of the following: 1) Material of which no part will ignite and burn when subjected to fire, or 2) Material having a structural base of noncombustible material as defined in the previous item, with a surfacing material not over 1/8 inch thick, which has a flame-spreading rating of 50 or less (flame-spreading rating obtained to tests conducted in ASTM E 84-91a). Noncombustible does not apply to surface finish materials.
- Shaded fuel break - An area of varying width and perimeter where fuel continuity is interrupted sufficiently to prevent or inhibit a wildfire crossing it, and which contains a limited number of trees to be attractive and to provide some shaded ground within the fuel break area. Shade can also be provided by trees retained on the fuel break's perimeter.
- Slash - The remnants of tree limbing, thinning, and ground fuel reduction (i.e., branches, limbs, deadwood).
- Wildfire - A fire that spreads fast and is hard to control; an open fire which spreads unconstrained through the environment. If not quickly controlled, the result can be a fire storm, often termed a "conflagration," which destroys large amounts of property and threatens lives. Since prehistoric times, wildfires have been a natural force in shaping and changing Colorado's landscape. Many of the native tree, brush, and grass species have evolved into fire-dependent vegetation. Some are so fire dependent that their combustibility increases with age, thus assuring renewal and continuation of the species. Lightning provides the ignition for these naturally occurring fires. Human-caused fires may also become firestorms.
- Wildfire Hazard - As defined in the Colorado Land Use Act is a wildfire phenomenon which is so adverse to past, current or foreseeable construction or land use as to constitute a significant hazard to the public health and safety or to property. The term includes but is not limited to slope and aspect; wildfire behavior characteristics; and existing vegetation types. Wildfires are becoming more intense and frequent due to the last 100 years of fire suppression, which has resulted in an accumulation of live and dead fuels; and the increasing recreational use and human habitation. The continued growth of development and recreational activities in the areas of greatest vulnerability gives rise to increasing risks. In 1994, the nation, including Boulder County, experienced the most demanding wildfire year ever with over $1 billion dollars spent to put out 74,000 wildfires, 28 firefighters lost, and 4 million acres burned. Over the last 5 years (1990-1995), an average of 500 homes were consumed per year to wildfires. In Boulder County, the Black Tiger Fire of 1989 and the Olde Stage Fire of 1990 combined resulted in the loss of 66 homes and over 6,000 acres at a significant cost to the county.
- Wildland - An area in which development is essentially non-existent, except for roads, railroads, powerlines, and similar transportation facilities. An example of area in the County that conforms to this description is the North Saint Vrain drainage.
- Wildland Urban Interface - A term used to describe where homes and development encroach on the native vegetation such as the grass and forested covered slopes of the plains, the foothills and/or the mountain areas. This human encroachment into the wildland is an area at risk to wildland fires or wildfires.