A review of US wildland firefighter entrapments: trends, important environmental factors and research needs

Abstract

Wildland firefighters in the United States are exposed to a variety of hazards while performing their jobs. Although vehicle accidents and aircraft mishaps claim the most lives, situations where firefighters are caught in a life-threatening, fire behaviour-related event (i.e. an entrapment) constitute a considerable danger because each instance can affect many individuals. In an attempt to advance our understanding of the causes of firefighter entrapments, a review of the pertinent literature and a synthesis of existing data were undertaken. Examination of the historical literature indicated that entrapment potential peaks when fire behaviour rapidly deviates from an assumed trajectory, becomes extreme and compromises the use of escape routes, safety zones or both. Additionally, despite the numerous safety guidelines that have been developed as a result of analysing past entrapments, we found issues with the way factual information from these incidents is reported, recorded and stored that make quantitative investigations difficult. To address this, a fire entrapment database was assembled that revealed when details about the location and time of entrapments are included in analyses, it becomes possible to ascertain trends in space and time and assess the relative influence of various environmental variables on the likelihood of an entrapment. Several research needs were also identified, which highlight the necessity for improvements in both fundamental knowledge and the tools used to disseminate that knowledge.

Severe Fire Danger Index: A Forecastable Metric to Inform Firefighter and Community Wildfire Risk Management

“…The development of an index that tracks well with observed fire activity, and the technical capacity to forecast and map episodes of severe fire danger, together form the foundation of an operational, early-warning system targeted at improving wildland firefighter situational awareness and safety. At a minimum, increased fire behavior may postpone containment opportunities [47,48], but under worst-case scenarios, rapid and unexpected accelerations towards extreme fire behavior can lead to wildland firefighter entrapments [49]. To directly evaluate the capacity of the SFDI to indicate life-threatening fire environments, a wildland firefighter entrapment database [49] containing 178 events between 1979-2017 was intersected with the fire danger climatology.…”

“…At a minimum, increased fire behavior may postpone containment opportunities [47,48], but under worst-case scenarios, rapid and unexpected accelerations towards extreme fire behavior can lead to wildland firefighter entrapments [49]. To directly evaluate the capacity of the SFDI to indicate life-threatening fire environments, a wildland firefighter entrapment database [49] containing 178 events between 1979-2017 was intersected with the fire danger climatology. Each record in this database was assigned an ERC', BI' and SFDI value coinciding with the location and date of the entrapment.…”

A Classification of US Wildland Firefighter Entrapments Based on Coincident Fuels, Weather, and Topography

“…Part of the problem has been that, until recently, quantitative data related to firefighter entrapments have not been widely available. Page et al [21] have compiled a database of firefighter entrapments involving burnovers that occurred within the conterminous US (CONUS) since 1979, which includes the location, date, time, number of people involved, number of fatalities, and quality of the location information for entrapments reported from all known sources. The date and location information contained within this database allows entrapments to be linked to historical spatial layers of various environmental data so that a comprehensive dataset of the fire environment during the day of the entrapment and at the entrapment location can be compiled.…”

“…All known firefighter entrapments that occurred within CONUS from 1979 to 2017 were obtained from the Fire Sciences Lab Merged Entrapment Database (https://www.wfas.net/entrap/, accessed on 17 July 2019) [21]. Those entrapments listed as burnovers (excluding near-misses and close calls) that had accurate location information were extracted from the full dataset and used for subsequent analysis.…”

“…Extreme fire behavior, as well as what is often referred to as 'blow-up' [13] or 'eruptive' [14] fire behavior, has been linked to firefighter fatalities both in the US and other parts of the world [15][16][17][18][19]. It is thought that a sudden, unexpected increase in rate of spread associated with eruptive fire behavior, particularly on steep slopes and in canyons, limits the ability of firefighters to adapt or escape, thereby increasing the likelihood of entrapment [20][21][22]. Table 1.…”