Wake County Hazard Mitigation Plan - January 2020

SECTION 4: RISK ASSESSMENT

Table 4.42 – Consequence Analysis - Flood

Category

Consequences

Public

Localized impact expected to be severe for incident areas and moderate to light for other adversely affected areas. First responders are at risk when attempting to rescue people from their homes. They are subject to the same health hazards as the public. Flood waters may prevent access to areas in need of response or the flood may prevent access to the critical facilities themselves which may prolong response time. Damage to personnel will generally be localized to those in the flood areas at the time of the incident and is expected to be limited. Floods can severely disrupt normal operations, especially when there is a loss of power. Damage to facilities in the affected area may require temporary relocation of some operations. Localized disruption of roads, facilities, and/or utilities caused by incident may postpone delivery of some services. Buildings and infrastructure, including transportation and utility infrastructure, may be damaged or destroyed. Impacts are expected to be localized to the area of the incident. Severe damage is possible. Chemicals and other hazardous substances may contaminate local water bodies. Wildlife and livestock deaths possible. The localized impact is expected to be severe for incident areas and moderate to light for other areas affected by the flood or HazMat spills. Local economy and finances will be adversely affected, possibly for an extended period of time. During floods (especially flash floods), roads, bridges, farms, houses and automobiles are destroyed. Additionally, the local government must deploy firemen, police and other emergency response personnel and equipment to help the affected area. It may take years for the affected communities to be re-built and business to return to normal. Ability to respond and recover may be questioned and challenged if planning, response, and recovery are not timely and effective.

Responders

Continuity of Operations (including Continued Delivery of Services)

Property, Facilities and Infrastructure

Environment

Economic Condition of the Jurisdiction

Public Confidence in the Jurisdiction’s Governance

Hazard Summary by Jurisdiction The following table summarizes flood hazard risk by jurisdiction. To account for increased risk of flood due to stormwater and flash flooding, communities with between 2 and 12 flash flood events in the period from 2007-2018 were assigned a probability rating of 3, and communities with over 12 flash flood events during this period were assigned a probability rating of 4. Communities with 10% or more of their land area in the SFHA were assigned a spatial extent of 3. All other factors do not vary by jurisdiction.

Jurisdiction Wake County

Probability Impact

Spatial Extent

Warning Time

Duration

Score

Priority

3 3 3 3 2 3 2 3 4 2 3 2 3

3 3 3 3 3 3 3 3 3 3 3 3 3

3 2 2 2 2 2 2 2 2 2 2 2 2

3 3 3 3 3 3 3 3 3 3 3 3 3

3 3 3 3 3 3 3 3 3 3 3 3 3

3.0 2.8 2.8 2.8 2.5 2.8 2.5 2.8 3.1 2.5 2.8 2.5 2.8

H H H H H H H H H H H H H

Apex Cary

Fuquay-Varina

Garner

Holly Springs

Knightdale Morrisville

Raleigh

Rolesville

Wake Forest

Wendell Zebulon

Wake County Multi-Jurisdictional Hazard Mitigation Plan 2019

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