SECTION 4: RISK ASSESSMENT
All of Wake County has a relatively low burn probability, with the highest probabilities reaching a rating of 5 or less. The areas of moderate burn probability are located primarily in the southeast of the county in Fuquay-Varina, Garner, and the unincorporated county, with an additional small cluster in the northeast in and around Zebulon. The probability of wildfire across the county is considered possible, defined as between a 1% and 10% annual chance of occurrence. While all jurisdictions fall within this threshold, the communities containing moderate burn probability, noted above, have a comparatively higher probability of occurrence.
Probability: 2 – Possible CLIMATE CHANGE
Wildfires are usually prevalent with a combination of high temperatures and dry conditions, combustible fuels and an ignition source. Climate change has been linked to longer, warmer and drier conditions in the Southeast, exacerbating key potential conditions for a wildfire to spread. VULNERABILITY ASSESSMENT
METHODOLOGIES AND ASSUMPTIONS
Population and property at risk to wildfire was estimated using data from the NCEM IRISK database, which was compiled in NCEM’s Risk Management Tool. Within IRISK, wildfire hazard areas were determined using the Wildland Fire Susceptibility Index (WFSI). The following parameters were applied:
• Areas with a WFSI value of 0.01 – 0.05 were considered to be at moderate risk.
• Areas with a WFSI value greater than 0.05 were considered to be at high risk.
• Areas with a WFSI value less than 0.01 were considered to not be at risk.
The WFSI integrates the probability of an acre igniting and the expected final fire size based on the rate of spread in four weather percentile categories into a single measure of wildland fire susceptibility. Due to some necessary assumptions, mainly fuel homogeneity, it is not the true probability. But since all areas of the state have this value determined consistently, it allows for comparison and ordination of areas of the state as to the likelihood of an acre burning. PEOPLE Wildfire can cause fatalities and human health hazards. Ensuring procedures are in place for rapid warning and evacuation are essential to reducing vulnerability. Table 4.127 details the population estimated to be at risk to wildfire according to the NCEM IRISK database. Table 4.127 – Estimated Population Impacted by Wildfire
Elderly Population At Risk
All Children Population
Population At Risk
All Elderly Population
Children At Risk
Total Population
Jurisdiction
Number Percent
Number Percent
Number Percent
Raleigh
476,892
14
0%
53,945
2
0%
26,904
1
0%
Apex
57,525
0
0%
5,963
0
0%
3,912
0
0%
Cary
164,869
0
0%
19,866
0
0%
9,432
0
0%
Fuquay-Varina
32,177
488
2%
4,432
86
2%
2,204
43
2%
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 239
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