The RCI Project Team consisted of experts in the fields of fire behavior and suppression, forest and range ecology, and geographic information systems (GIS). The RCI Project Team collaborated to complete a Community Risk/Hazard Assessment for each of the identified communities in Elko County. The RCI Field Teams included a Fire Specialists with extensive working wildland fire experience in Nevada and Resource Specialists experienced in the natural resource environment of the Great Basin.
The RCI Project Team used standardized procedures developed from the Draft Community Wildland Fire Assessment For Existing and Planned Wildland Residential Interface Developments in Nevada (Nevada’s Wildland Fire Agencies, Board of Fire Directors, April 2001; revised 2002). This approach incorporates values for fuel hazards, structural hazards, community preparedness, and fire protection capabilities into an overall community rating. A glossary of wildland fire terms frequently used in describing assessment results and recommendations is included in Appendix A.
GIS Specialist on the RCI Project Team compiled and reviewed existing statewide geospatial data to create maps for recording baseline data and data verification. Data sources for the maps were the Nevada Fire Safe Council, the Nevada Department of Transportation, the US Forest Service, and the Bureau of Land Management. Datasets and sources utilized are summarized in Table 2-1.
Dataset | Data Source |
---|---|
Land Ownership | Bureau of Land Management Nevada State Office Mapping Services |
Vegetation Communities | Nevada Gap Analysis Program Data, Utah Cooperative Fish and Wildlife Research Unit, Utah State University |
Topography | USGS Digital Elevation Models and Topographic Maps |
Fire Suppression Resources | Field Interviews |
Roads | “TIGER” Census data 2000 |
Current Aerial Photographs | USGS Digital Orthophoto Quadrangles (1994, 1996, or 1998) |
Fuel Hazard Classes | Bureau of Land Management Utah State Office Fire Hazard Potential Data |
Fire History | Bureau of Land Management Nevada State Office Mapping Services US Forest Service Humboldt-Toiyabe Supervisor’s Office National Interagency Fire Center, Boise ID |
Recorded wildfire history was mapped using Bureau of Land Management and US Forest Service datasets and GIS databases that identify wildfire perimeters on federally managed lands from 1980 to 2003. Fire perimeters were mapped by agency personnel using a global positioning system (GPS) and screen digitizing on source maps with a minimum detail level of 1:250,000. The datasets have been updated at the Bureau of Land Management Nevada State Office and the US Forest Service Humboldt-Toiyabe National Supervisor’s Office at the end of each fire season from information provided by each Nevada Bureau of Land Management Field Office and Humboldt-Toiyabe Ranger District. The datasets are intended to be the central sources of historical GIS fire data used for fire management and land use planning on federal lands.
In addition to the fire perimeter information, point data for all fire ignitions within Nevada from 1980 to 2003 was obtained from the National Interagency Fire Center (NIFC) database in Boise, Idaho. This dataset includes an ignition point coordinate and an acreage component as reported to NIFC through a variety of agencies. This data is summarized in Table 3-2 and provides the ignition point locations for the maps in this report. In many cases, the ignition point location is only accurate to within the section; in such cases, the point coordinate is located in the section center on the maps.
The wildfire history and ignition history data were used to formulate risk ratings and develop recommendations specific to areas that have been repeatedly impacted by wildland fires. Observations made from the RCI Project Team and comments from local fire agencies were used to develop recommendations in areas without recent wildfire activity where accumulations of fuels or expansion of urban development into the interface area represents a growing risk.
The wildland-urban interface is the place where homes and wildland meet. This project focused on identifying risks and hazards in the wildland-urban interface areas countywide by assessing each community individually. Site-specific information for each community was collected during field visits in Elko County conducted August 23 through September 3, 2004. The predominant conditions recorded during these site visits were used as the basis for the Community Risk/Hazard Assessment ratings.
The Fire Specialists on the RCI Project Team assigned an ignition risk rating of low, moderate, or high to each community assessed. This rating was based on four sources of information: the interpretation of the historical record of ignition patterns and fire polygons provided by the National Interagency Fire Center, Bureau of Land Management, and US Forest Service databases; interviews with local fire department personnel and regional Fire Management Officers; field visits to each community; and the professional judgment of the RCI Fire Specialists based on their professional experience with wildfire ignitions in Nevada.
The Community Hazard Assessments were completed using methodology outlined in the Draft Community Wildland Fire Assessment For Existing and Planned Wildland Residential Interface Developments in Nevada (Nevada’s Wildland Fire Agencies 2001, revised 2002). This system assigns hazard ratings of low through extreme based on the scoring system shown in Table 2-2 and detailed in Appendix B.
Hazard Category | Score |
---|---|
Low Hazard | < 41 |
Moderate Hazard | 41-60 |
High Hazard | 61-75 |
Extreme Hazard | 76+ |
To arrive at a score for the community, five primary factors that affect potential fire hazard were assessed: community design, construction materials, defensible space, availability and capability of fire suppression resources, and physical conditions such as fuel loading and topography. A description of each of these factors and their importance in developing the overall score for the community is provided below. Individual community score sheets are provided at the end of each community assessment.
Aspects of community design account for 26 percent of the total assessment score. Many aspects of community design can be modified to make a community more fire safe. Factors considered include:
The type of materials used for building construction accounts for sixteen percent of the total hazard assessment score. While it is not feasible to expect all structures in the wildland-urban interface area to be rebuilt with non-combustible materials, there are steps that can be taken to reduce the risks associated with hazardous construction in the interface area. Factors considered in the assessment include:
Defensible space accounts for sixteen percent of the hazard assessment score. The density and type of fuels around a home determines the potential fire exposure levels to the home. A greater volume of trees, shrubs, dry weeds, dry grass, woodpiles, and other combustible materials near the home will ignite more readily, produce more intense heat during a fire, and increase the threat of property damage or loss. Defensible space is one of the factors that homeowners can easily manipulate in order to improve the chances that a home or other property will avoid damage or complete lost from a wildfire.
The availability and capability of fire suppression resources account for sixteen percent of the total hazard assessment score. Knowledge of the capabilities or limitations of the fire suppression resources in a community can help the residents take action to maximize the resources available. Factors considered in the assessment include:
Physical conditions account for 26 percent of the hazard rating. Physical conditions include slope, aspect, topography, fuel type, and fuel density. With the exception of changes to the fuel composition, the physical conditions in and around a community cannot be altered to make the community more fire safe. An understanding of how these physical conditions can influence fire behavior is essential to planning effective preparedness activities such as fuel reduction treatments. Physical conditions considered in the assessment include:
Fuel hazard maps were initially generated by the Bureau of Land Management (Nevada and Utah State Offices) using wildfire hazard delineations derived from vegetation data (Nevada GAP Analysis Program satellite dataset at thirty-meter resolution). A total of 65 vegetation types were mapped statewide and reclassified into four wildfire hazard categories (low, moderate, high, and extreme) based on the anticipated fire behavior for each vegetation cover type. For example, pinyon-juniper cover types were generally rated as extreme fuel hazards, while sparse shadscale cover types were rated as low fuel hazards.
The RCI Project Teams visited high and extreme fuel hazard communities and verified the Bureau of Land Management hazard information by comparing the hazard ratings on the existing fuel hazard map to vegetation, slope, and aspect conditions directly observed in the field. Where necessary, changes to the ratings were drawn on the maps and used to update the wildfire hazard potential layer in the project database. Photo points were established in high and extreme fuel hazard areas to monitor future changes in the fuel hazard conditions. Fuel hazard mapping was completed and figures prepared for all communities with high or extreme community hazard ratings. Photos of representative fuel types in Elko County are included in Appendix C.
Fire Specialists on the RCI Project Team described a worst-case wildfire scenario for each community based on the analyses of the severe fire behavior that could occur given a set of weather conditions, observed fuel load conditions, and minimal fire suppression resources. The worst-case scenario does not describe the most likely outcome of a wildfire event in the interface, but illustrates the potential for damage if a given set of conditions were to occur simultaneously. The worst-case scenarios are described in this document for public education purposes and are part of the basis for the fuel reduction recommendations.
The Fire Specialists on the RCI Project Team interviewed local fire department personnel and regional agency Fire Management Officers to obtain information on wildfire training, emergency response time, personnel and equipment availability, evacuation plans, pre-attack plans, and estimates of possible worst-case scenarios. Local fire personnel reviewed maps showing the history of wildfires to ensure that local information on wildfires was added to the datasets when possible. A list of fire agency personnel contacted for information used in the assessments is included in Appendix D.
A wide variety of treatments and alternative measures can be used to reduce ignition risks, mitigate fire hazards, and promote fire safe communities. Proposed recommendations typically include physical removal or reduction of flammable vegetation, increased community awareness of the risk of fires and how to reduce those risks, and coordination among fire suppression agencies to optimize efforts and resources. The RCI Project Team met repeatedly to analyze community risks, treatment alternatives, and treatment benefits. Treatment recommendations to reduce existing risks and hazards were formulated based upon professional experience, the hazard assessment results, and information developed in conjunction with the “Living with Fire” publications, the National Fire Plan, and FIREWISE resources (National Fire Plan website: http://www.fireplan.gov/reports/7-19-en.pdf; FIREWISE website: http://www.firewiese.org; and the Nevada Cooperative Extension publications). The recommendations included in this report are considered high priorities for individual communities and are presented in a relative order of importance.