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4.M Fire Services and Hazards

where new developments are adjacent to these vegetation communities, known as the wildland-
urban interface, face the greatest wildfire risk due to the increased potential for ignition.

The frequency of wildfires for an area depends largely on the age of vegetation. During
the initial years of renewed vegetation, the chance of a wildfire will be less as younger
vegetation will have higher moisture content and are less combustible. As the vegetation ages,
dead and dying brush accumulate, building up fuel and creating high risk conditions for large-
scale wildfires. Generally, wildfires occurrence is cyclical, with small fires occurring on an
annual basis and large-scale fires occurring every 10 years.

(c) Topography

Topography is a critical factor during fire fighting efforts since slope conditions can
affect both fire spread and accessibility. The steeper the slope, the faster a wildfire will travel.
Fires will usually travel uphill (in the direction of the ambient wind) and create updraft
conditions that can accelerate the spread of fire. In addition, uphill fires can preheat fuel further
up the hill due to the rising smoke and flames. Steep slopes can also impede access for fire
fighting crews and delay fire suppression efforts.

The project site is located in an area characterized by rolling hills with the majority of
slopes averaging less than 25 percent. However, due to the presence of slopes in excess of
25 percent, the County designates areas of the site as being within a County Hillside
Management zone.

3. PROJECT IMPACTS

a. Thresholds of Significance

For the purpose of this analysis, impacts with regard to fire services and hazards are
considered significant if:

• The project’s fire service demand will not be adequately served by existing and
proposed facilities and improvements;

• The project would not provide adequate emergency access to the project site;

• The project would result in inadequate response times for project residents;

County of Los Angeles Department of Regional Planning Skyline Ranch Project
PCR Services Corporation July 2009

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