SECTION 4: RISK ASSESSMENT
4.6 CONCLUSIONS ON HAZARD RISK PRIORITY RISK INDEX
As discussed in Section 4.3 Risk Assessment Methodology and Assumptions, the Priority Risk Index was used to rate each hazard on a set of risk criteria and determine an overall standardized score for each hazard. The conclusions drawn from this process are summarized below. Table 4.144 summarizes the degree of risk assigned to each identified hazard using the PRI method. Table 4.144 – Summary of PRI Results
Spatial Extent
Warning Time < 6 hours > 24 hours < 6 hours > 24 hours
PRI Score
Hazard
Probability
Impact
Duration
Dam Failure
Possible
Critical
Negligible
< 1 week > 1 week < 6 hours < 1 week < 1 week < 24 hours
2.4 2.5 1.9 3.3 2.8 2.9 2.8 1.2 2.3 2.1
Drought
Likely
Minor Minor
Large Large Large Small Large Large
Earthquake Extreme Heat
Unlikely
Highly Likely
Critical Critical Critical Critical
Flood
Likely Likely
6 to 12 hours
Hurricane & Tropical Storm
> 24 hours > 24 hours
Infectious Disease
Possible Unlikely
> 1 week
Landslide
Minor Minor Minor
Negligible 6 to 12 hours < 6 hours
Severe Weather: Hail 1
Highly Likely
Small
6 to 12 hours < 6 hours
Severe Weather: Lightning 1 Highly Likely
Negligible 6 to 12 hours < 6 hours
Severe Weather: Thunderstorm Winds 1 Severe Winter Storm
Highly Likely
Limited
Large
6 to 12 hours < 6 hours
3.0
Highly Likely
Limited Critical Limited
Large Small
> 24 hours < 6 hours < 6 hours
> 1 week < 6 hours < 1 week
3.0 2.7 2.5
Tornado Wildfire
Likely
Possible
Moderate
Hazardous Materials Incident
Highly Likely
Limited
Negligible
< 6 hours
< 24 hours
2.6
Cyber Threat
Possible Unlikely Unlikely
Minor
Small Small
< 6 hours < 6 hours < 6 hours
> 1 week > 1 week < 6 hours
2.5 2.7
Radiological Emergency
Catastrophic
Terrorism 2.2 1 Note: Severe Weather hazards average to a score of 2.5 and are therefore considered together as a medium risk hazard. Catastrophic Negligible The results from the PRI have been classified into three categories based on the assigned risk value which are summarized in Table 4.145: • High Risk – Widespread potential impact. This ranking carries a high threat to the general population and/or built environment. The potential for damage is widespread. • Medium Risk – Moderate potential impact. This ranking carries a moderate threat level to the general population and/or built environment. Here the potential damage is more isolated and less costly than a more widespread disaster. • Low Risk – Minimal potential impact. The occurrence and potential cost of damage to life and property is negligible or nonexistent.
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 270
Made with FlippingBook interactive PDF creator