IV. Existing Wildfire Risk Factors

The Virginia Highlands is identified as a community-at-risk by the State of Nevada. The Highlands is described as an urban interface community with structures interspersed throughout the wildland area. The Nevada Fire Board categorized the Highlands as being at high risk for wildfire based upon the occurrence of a continuous expanse of vegetative fuel (pinyon and juniper) with a high propensity to carry crown fires or high intensity surface fires in close proximity to structures. Additional risk factors identified included limited access routes, limited water supply, and limited fire fighting capability.

Vegetation and Fuels

Vegetation in the Virginia Highlands is closely correlated to soils and climate. Specific soil types such as loams, clays, and gravelly loams support distinct plant communities under natural conditions. Presently, the predominant vegetation in the Highlands Community consists of dense stands of singleleaf pinyon intermixed with Utah juniper (commonly referred to as pinyon-juniper, or P-J woodlands). Under natural conditions with periodiclower intensity wildfires, woodlands were traditionally confined to the higher elevations and steeper slopes.

The P-J woodlands evolved with what ecologists refer to as a “stand-destroying fire regime”. P-J fires often involve the tree canopy, which branches all the way to the ground and typically destroys much or all of the stand. Pinyon trees have relatively thin bark and ladder fuels are very common. The tree is designed by nature to be completely destroyed during fire.[1] Reforestation of a P-J woodland after a fire first requires an established brush community for shading sensitive tree seedlings.

Natural landscape patterns characterized by discontinuous expanses of fuels in the P-J woodlands and shrublands created natural controls on fuel loads resulting in more frequent but much less severe fires. The project area, as well as most of the western United States, has been subjected to control of naturally occurring wildfire over the last 100 years. A lengthy period without fire and limited woodcutting hasallowed the P-J woodlands to encroach over an extended area, creating tree canopy coverage as high as 60 percent and the loss of the diverse shrublands. Human incursion into these wildlands over the last 50 years now excludes the option of returning to a natural fire routine.

Currently, the ecological condition of the woodlands in the Virginia Highlands is fair to poor. The woodlands are over-grown and unhealthy. Evidence of a declining ecological condition includes changes in wildlife habitat such as reduced vegetation diversity and structure, and displacement of many wildlife species associated with the brushy, open habitats.

Pinyon trees within the existing overgrown woodlands have conspicuously displaced shrublands that should naturally be dispersed throughout the project area. Under natural conditions, a mosaic pattern of shrubs and trees would occur across the landscape as a result of periodic uncontrolled wildfire that would create openings. After a fire, in the absence of dominance by cheatgrass, brush species immediately begin to reoccupy the woodland site. Later, pinyon and juniper species become established in the shade of the brush.

Fuel loading in the Virginia Highlands Community ranges from MODERATE to HIGH to EXTREME. There is little difference between the canopy fuels and understory fuels since tree limbs on the pinyon and juniper trees extend to the ground, and many of the brush species are quite tall. A wildland fire in this fuel type will be high intensity through a single, thick fuel surface. The heaviest loadings are in the over-grown P-J woodland.

Winds and fuel moisture may produce flame lengths of 20-30 feet in the surface fuels and 80-100 feet or more in the trees. Depending on the degree of slope, flame lengths running uphill could reach greater than 100 feet under worst-case conditions.

Road Access

Access to the area is from Highway 341. Cartwright Road is the main entry road to the north in the area of Fivemile Flat. Lousetown Road enters the development just north of Virginia City, also from Highway 341. These two main arteries into the subdivision are paved and intersect near Storey County Fire Department Station #2 in the Highlands. Residential roads are typically 20 feet wide with good drainage from a minimal road base. Base materials appear to be a mix of gravel and native soil.

Access across the project area is difficult in many places. The road network is generally winding and steep. Numerous roads dead-end at driveways. Navigation from one artery to another on residential streets involves numerous turns. Many roads are constructed straight up the slopes, making them difficult at best to drive. A few roads are impassable to emergency equipment, especially under wet or icy conditions.

Road signs are also difficult for fire fighters to read in many places. Some are non-reflective, small, and positioned at various heights. Many are made of wood and not permanently affixed in place. During a wildland fire, these signs may be destroyed making access to specific structures impossible for fire fighters, especially resources brought in from cooperating agencies that are not familiar with the neighborhoods.

Driveway Access

Some residential driveways have even more difficult accessibility. Many are narrow and crowded by trees and rocks at the entrance, with switchback turns and no turn-around point for fire apparatus to maneuver within. Fire fighting equipment would be unable to pass through these areas if ablaze, thereby disallowing fire protection/suppression activities at many homes. Homeowners could find themselves trapped with no escape route to safety if fire closed off the access.

Address identification is also lacking for the most part throughout the project area. Intermittent house numbers and interspersed vacant lots between existing addresses makes it critical to have clear, readily visible address identification signs from the road. The fire department is making reflective address signs available for all homeowners in the Virginia Highlands Community.

Utilities

All electrical service to the area consists of overhead wires. This triggers several hazards. A fire may start from arcing power lines during windy conditions. During a fire the power lines may short out or the poles may burn causing a power outage. Energized power lines may fall creating an additional hazard for civilians evacuating the area or firefighters fighting the fire. Many homeowners have portable generators in case of a power failure. Under these conditions, homeowners may still be able to operate the pumps on wells for fire protection.

Large propane tanks are located throughout the area, in many cases close to structures without adequate clearance from brush and trees. This creates a possible explosion hazard.

Building Materials

Homes within the Highlands Community have been built with a variety of roof materials and exterior wall siding products. It appears that most of the homes have composition roofs, but some have highly flammable shake shingle roofs. Most of the exterior walls observed during neighborhood reconnaissance were wood products.

Spacing between home sites is not a problem due to the one-acre minimum lot sizes. However, in some cases there are out buildings that could be at risk if an adjacent structure is heavily involved with fire.

Many homes have large glass picture windows that will create a problem if the radiant heat of a wildland fire is too close to that portion of the structure. Extreme heat from wildfires can cause glass to explode and expose the interior of the home to flying ash and embers.

Wood deck, open overhanging rafters, and other similar architectural features can also become traps for flying ash and embers.

Emergency Wildfire Response

The SCFD is formed under NRS Chapter 473, which assigns the State of Nevada the lead role in wildfire management. The NDF Comprehensive Wildfire Management Program includes public education, prevention, hazardous fuels reduction, suppression, and wildfire rehabilitation. Both NDF and SCFD are also collaborating agencies in the Sierra Front Wildfire Cooperators. As such, resources from various regional fire protection agencies would respond in the event of a wildfire emergency in the Virginia Highlands. Response time would depend upon available resources in the area.

After the first alarm, in the event that the SCFD initial attack was unsuccessful, the wildfire suppression effort would come under the control of NDF. During the fire season, NDF deploys additional firefighters and equipment to Storey County Fire Station #2 in the Highlands. Firefighters will initially respond with two pieces of equipment and will be backed up by local volunteer firefighters from the area. The availability of additional help including air attack and dozers will be dispatched from Minden and will vary depending on the time of day and the day of the week.

SCFD has established locations for their Command Post, Staging Areas, Safe Zones, and a community evacuation plan. The evacuation zones are shown in Figure 3. Residents could be notified of a need to evacuate the area through the use of a siren system. The Virginia Highlands evacuation plan is included in Appendix C.

Worst Case Scenario

SCFD reports that numerous single-tree lightning strike fires occur during the summer in the general area. They are usually controlled before burning beyond the tree of origin. Historically, large fires in the general area have started to the west and north of the Virginia Highlands. Fires of this nature are not the greatest threat. In that type of scenario, the local fire agencies have time to deploy resources, both ground and air, to protect the Highlands Community before the situation becomes critical.

An example of a worst-case scenario fire in the Highlands is:

A fire that starts in the southwest area near Hwy 341 and Cartwright Road in mid-afternoon. Winds in excess of 35mph from the southwest could move the fire in a northeast direction toward areas with extreme fuel loads and very limited road access.

The dense woodlands and steep topography in this area almost assure that the worst-case scenario fire will be carried through the canopy of the Pinyon trees, referred to as a “crown fire”. A crown fire is the most perilous of all fire conditions and quite frequently is catastrophic in nature since the danger to firefighters is generally too great to deploy ground crews. Virtually all of the vegetation, the homes, and the people in the path of a crown fire are at risk of destruction in the absence of a well-executed and aggressive fuels management plan. In addition to limited possibilities for structure protection, there is a high possibility of loss of life in the worst-case scenario of a wind-driven crown fire.

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[1] In comparison, other pine trees have evolved to depend on fire for their continued existence. For example, Ponderosa Pine has thick bark and a self-pruning habit for losing its lower branches. With fewer “ladder fuels” there is less chance of a stand-destroying crown fire except under extreme fire behavior conditions.