Yellowstone National Park - Fire Monitoring (U.S. National Park Service)

A snag in a recent burn blown apart by lightning.

Fire Monitoring

A report of a fire start is received by the Yellowstone Wildland Fire Dispatch Office and fire monitors are sent to investigate. First, monitors determine the cause of the fire (human-caused or lightning strike). Fires caused by human activity are suppressed but natural fires are allowed to burn as long as they do not threaten people, property or resource values. After determining that a fire start, or ignition, is natural, monitors collect information that will allow the Fire Management Office to decide what management action should be taken. If management criteria are met, the fire may be left to burn as a natural ecosystem process. Such fires are called wildland fires for resource benefit (WFRB) or fire-use fires. Once a fire is designated as a fire-use fire it must be managed. Fire Management requires information on weather, fuels, and values at risk which fire monitors provide. Monitors record the fire location, hourly weather, site vegetation, slope-aspect, fuel loading, flame length, and rate of spread. Digital images are taken depicting fire behavior and the fuels that are carrying the fire.

Fire monitors record fuel loading and weather information. 2003 Fan Creek Fire.

Fire monitors also map the perimeter of the fire daily to help measure the fire’s progression. This information is relayed to the Fire Dispatch Office. Monitors also collect samples of fuels for moisture analysis. Fuels may include tree foliage, herbaceous vegetation, forest floor litter, and dead logs in various size classes. The fuel samples are weighed, dried in an oven, and re-weighed. The resulting fuel moisture figures allow fire managers to anticipate how intensely and quickly a fire will spread. Fire monitors may observe small, smoldering fires for a short time every few days. They may also camp out on large, remote fires for days or weeks at a time, continuing to collect information on fire behavior, fuels, and weather. Often fire monitors will deploy weather instruments such as a remote automated weather station. On larger fires, fire behavior analysts and long-term fire analysts are often utilized to help assess the fire conditions. They also use information provided by fire monitors to predict fire intensity and spread rate.

When they are not on fires, fire monitors collect daily fire weather information from stations around the park. Monitors measure temperature, precipitation, relative humidity, dew point, winds, fuel moisture, and lightning occurrence which are used to determine current and expected fire danger. This large volume of weather and fuel moisture data from all parts of the park is processed to identify areas of potentially problematic fire behavior in the event of an ignition.