2.1 Project Team

The RCI Project Team was composed of experts in the fields of fire behavior and suppression, geographic information systems (GIS), natural resource ecology, and forest health who collaborated to complete a Community Risk/Hazard Assessment for each community. Each RCI Project Team included a Fire Specialist with extensive wildland fire prevention and suppression experience in Nevada and a Resources Specialist 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 during the assessment process (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 wildfire management terms is included in Appendix A.

2.2 Base Map Data Collection

The RCI Project Team Geographic Information Specialists compiled and reviewed existing statewide geospatial data to create field maps for recording baseline data and performing data verification. Data sources for the maps were the Nevada Fire Safe Council, the Nevada Department of Transportation, the Natural Resource Conservation Service, the US Forest Service, and the Bureau of Land Management. Datasets and sources utilized are summarized in Table 2-1.

Table 2-1. Primary Datasets and Sources Utilized in the Storey County Community Wildfire Risk/Hazard Assessment

Spatial Data Set	Data Source
Land ownership	BLM Nevada State Office Mapping Services
Vegetation communities	Nevada Gap Analysis Program Data, Utah Cooperative Fish and Wildlife Research Unit, Utah State University
Topography	US Geological Survey Digital Elevation Models and Topographic Maps
Fire suppression resources	Field Interviews
Roads	“TIGER” Census data (2000)
Current aerial photographs	US Geological Survey Digital Orthophoto Quadrangles (1994, 1996, or 1998)
Soil surveys	BLM Nevada State Office Mapping Services Natural Resource Conservation Service “SSURGO” Website
Fuel types	BLM Nevada State Office Fire Hazard Potential Data
Fire history	BLM Nevada State Office Mapping Services National Interagency Fire Center - Boise, Idaho

Existing data was reviewed and the pertinent information was compiled on maps in GIS format. The RCI Project Teams verified the GIS data during field assessments. The GIS Specialists provided data management for quality assurance and accuracy of the statewide geospatial data as well as map production.

2.2.1 Wildfire History

Wildfire history was mapped using Bureau of Land Management datasets, US Forest Service datasets, and GIS databases that identify wildfire perimeters on federally managed lands, covering the past 21 years. This database was compiled by agency personnel using Global Positioning System (GPS) data and screen digitizing from source maps with a minimum detail of 1:250,000. This dataset has been updated at the BLM Nevada State Office and Humboldt-Toiyabe Supervisors Office at the end of each fire season from information provided by each Nevada BLM Field Office and Humboldt-Toiyabe Ranger District. The datasets are the central source of historical GIS fire data used to support fire management and land use planning on federal lands.

In some cases the RCI Project Team Fire identified additional fire perimeters not present in the BLM and USFS datasets as a result of interviews with local fire experts. Fires that occur on private lands are generally recorded on paper maps and have not been consistently included in federal agency GIS datasets. Additional fire locations identified during the interviews with local fire personnel were recorded on the field maps where possible and added to the project wildfire perimeter dataset.

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 surveyed-section; in such cases, the point coordinate is located in the section-center on the maps.

The wildfire and ignition history data was used to formulate risk ratings and to develop recommendations specific to areas that have been repeatedly impacted by wildland fires. Observations by the RCI Project Team and comments from the local fire agency personnel were also used to develop recommendations for each community where a significant buildup of fuels or expansion of urban development into the interface area represents a growing risk.

2.3 Community Risk/Hazard Assessment

The wildland-urban interface is the place where homes and wildland meet. This project focuses 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 conducted January 19-22, 2004. The predominant conditions recorded during these site visits were used as the basis for the Community Risk and Hazard Assessment ratings.

2.3.1 Ignition Risk Assessment Criteria

The RCI Project Team Fire Specialists assigned an ignition risk rating of low, moderate, or high to each community assessed. This rating is based on 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 local area Fire Management Officers; field visits to each community; and the professional judgment of the fire specialists based on their professional experience with wildland fire ignitions in Nevada.

2.3.2 Hazard Assessment Criteria

The Community Wildfire Risk/Hazard Assessments were completed using methodology outlined in the Draft Community Wildland Fire Assessment For Existing and Planned Wildland Residential Interface Developments in Nevada. This system assigns hazard ratings of low through extreme based on the scoring system given in Table 2-2 and detailed in Appendix B.

Table 2-2. Hazard Rating Point System Utilized in the Nevada Community Wildfire Risk/Hazard Assessment Project

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 presenting the point values assigned to each element in the hazard assessment score are provided at the end of each community assessment. Photographs of representative fuel types for each community are provided in Appendix C.

Community Design

Aspects of community design account for 26 percent of the total score of the hazard assessment. Many aspects of community design can be modified to make a community more fire safe. Factors considered include:

• Interface Condition. Community safety is affected by the density and distribution of structures with respect to the surrounding wildland environment. Four condition classes were used to categorize the wildland-urban interface: Classic Interface, Intermix, Occluded, and Rural. Definitions for each condition class are included in the glossary in Appendix A.
• Access. Design aspects of roadways influence the hazard rating assigned to a community. A road gradient of greater than five percent can increase response times for heavy vehicles carrying water. Roads less than twenty feet in width often impede two-way movement of vehicles and fire suppression equipment. Hairpin turns and cul-de-sacs with radii of less than 45 feet can cause problems for equipment mobility. Adequately designed secondary access routes and loop roads in a community can lower a hazard rating. Visible, fire-resistant street and address identification and adequate driveway widths also reduce the overall community hazard rating.
• Utilities. Poorly maintained overhead power lines can be a potential ignition source for wildfires. It is important to keep power line corridors clear of flammable vegetation, especially around power poles and beneath transformers. Fires have been known to start from arcing power lines or exploding transformers during wind storms or during periods of high electricity demand. Keeping flammable vegetation cleared from beneath power lines and around power poles reduces potential hazards from damaged power lines. Energized power lines may fall and create additional hazards for citizens and firefighters including blocked road access. Power failures are especially dangerous to a community without a backup energy source. Many communities rely on electric pumps to provide water to residents and firefighters for structure protection and fire suppression.

Construction Materials

Construction materials account for 16 percent of the total 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 address specific elements that strongly affect structure ignitability in the interface area. Factors considered in the assessment include:

• Structure Building Materials. The composition of building materials determines the length of time a structure can withstand high temperatures before ignition occurs. Houses composed of wood siding and wood shake roofing are usually the most susceptible to ignitions. Houses built with stucco exteriors and tile, metal, or composition roofing are able to withstand much higher temperatures and heat durations; thereby, they present a much lower ignition risk from firebrands or the proximity of advancing flames when defensible space conditions are adequate.
• Architectural Features. Unenclosed or unscreened balconies, decks, porches, eaves, or attic vents on homes can create drafty areas where sparks and embers can be trapped, smolder, and ignite, rapidly spreading fire to the house. A high number of houses within a wildland-urban interface area with these features implies a greater hazard to the community.

Defensible Space

Defensible space accounts for 16 percent of the assessment score. The density and type of fuel around a home determines the potential fire exposure and the potential for damage to the home. A greater volume of trees and 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 losing the home. Defensible space is one of the factors that homeowners can most easily manipulate in order to improve the chances that a home or other property avoids damage or complete loss from a wildfire.

Suppression Capabilities

Suppression capabilities account for 16 percent of the total assessment score. Knowledge of the capabilities or limitations of the fire suppression resources in a community can help county officials and residents take action to maximize the resources available. Factors considered in the assessment include:

• Availability, Number, and Training Level of Firefighting Personnel When a fire begins in or near a community, having the appropriate firefighting personnel available to respond quickly is critical to saving structures and lives. Whether there is a local, paid fire department, volunteer department, or no local fire department impacts how long it takes for firefighters to respond to a reported wildland fire or to a threatened community.
• Quantity and Type of Fire Suppression Equipment. The quantity and type of available fire suppression equipment has an important role in minimizing the effect of a wildfire on a community. Wildland firefighting requires specialized equipment.
• Water Resources. The availability of water resources is critical to fighting a wildland fire. Whether there is a community water system with adequate water supply, or whether firefighters must rely on local ponds or other drafting sites affect how difficult it will be for firefighters to protect the community.

Physical Conditions

The physical conditions that influence fire behavior account for 26 percent of the total assessment score. Physical conditions include slope, aspect, topography, typical local weather patterns, fuel type, and fuels density. With the exception of changes to the fuels composition, the physical conditions in and around a community cannot be altered to make the community more fire safe. Therefore, an understanding of how these physical conditions influence the fire behavior is essential to planning effective preparedness activities such as fuel reduction treatments. Physical conditions considered in the assessment include:

• Slope, Aspect, and Topography. In addition to local weather conditions, slope, aspect, and topographic features are also used to predict fire behavior. Steep slopes greatly influence fire behavior. Fire usually burns upslope with greater speed and longer flame lengths than on flat areas. Fire can burn downslope; however it usually burns downhill at a slower rate and with shorter flame lengths than in upslope burns. East aspect slopes in the Great Basin frequently have afternoon downslope winds that may rapidly increase downhill burn rates. West and south facing aspects are subject to more intense solar exposure, which preheats vegetation and lowers the moisture content of fuels. Canyons, ravines, and saddles are topographic features that are prone to higher wind speeds than adjacent areas. Fires pushed by winds grow at an accelerated rate compared to fires burning in non-windy conditions. Homes built mid-slope, at the crest of slopes, or in saddles are most at risk due to wind-prone topography in the event of a wildfire.
• Fuel Type and Density. Vegetation type, fuel moisture values, and fuel density around a community affect the potential fire behavior. Areas with thick, continuous, vegetative fuels carry a higher hazard rating than communities situated in areas of irrigated, sparse, or non-continuous fuels.

2.3.3 Fuel Hazard Mapping

The BLM Nevada and Utah State Offices, using the Nevada GAP Analysis Program satellite vegetation dataset, initially generated fuel hazard maps at 30-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 an extreme fuel hazard, while sparse shadscale cover types were rated as low fuel hazards.

The RCI Project Teams evaluated the interface areas around high and extreme hazard communities to verify the BLM 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 of the project database. Hazard mapping in Storey County was completed for the communities of Gold Hill, Virginia City, and the Virginia Highlands where high and extreme fuel hazard conditions exist.

2.3.4 Fire Behavior Worst-case Scenario

The RCI Project Team Wildfire Specialists described the worst-case wildfire scenarios based on their analyses of the severe fire behavior that could occur given a set of weather conditions, observed fuel load conditions, slope, aspect, and minimal fire suppression resources. The drought conditions and dry vegetation in combination with steep slopes or high winds can create situations in which the worst-case wildfire scenario can occur. The worst-case wildfire scenario does not describe the most likely outcome of a wildfire event in the interface but it illustrates the potential for damage if a given set of conditions were to occur simultaneously. The worst-case wildfire scenarios are described in this document for public education purposes and are part of the basis for the fuel reduction recommendations. Typical weather conditions including temperature, relative humidity, wind speed and direction, and time of day also contribute to actual fire behavior (Campbell, 1991).

2.4 Interviews with Fire Personnel

The RCI Project Team interviewed local fire department personnel and local area Fire Management Officers to obtain information on wildfire training, emergency response time, personnel and equipment availability and capability, evacuation plans, pre-attack plans, and estimates of possible worst-case wildfires scenarios. Local fire personnel reviewed maps showing the history of wildfires to ensure that local information on wildland fires was included. A list of fire agency personnel contacted for information used in the assessments is included in Appendix D.

2.5 Recommendation Development

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 use of 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 community hazard score, and information developed in conjunction with the Living With Fire publications, National Fire Plan, and FIREWISE resources (National Fire Plan website; FIREWISE website; and Nevada Cooperative Extension publications).