SECTION 4: RISK ASSESSMENT
Figure 4.25 – NWS Wind Chill Temperature Index
Source: http://www.nws.noaa.gov/om/winter/windchill.shtml
The greatest snowfall amount recorded in the Wake County planning area was 17.8 inches, recorded on March 2, 1927 at the Raleigh weather station.
Impact: 2 – Limited
Spatial Extent: 4 – Large
The entirety of North Carolina is susceptible to winter storm and freeze events. Some ice and winter storms may be large enough to affect several states, while others might affect limited, localized areas. The degree of exposure typically depends on the normal expected severity of local winter weather. Wake County is accustomed to smaller scale severe winter weather conditions and often receives winter weather during the winter months. Given the atmospheric nature of the hazard, the entire County has uniform exposure to a winter storm. HISTORICAL OCCURRENCES To get a full picture of the range of impacts of a severe winter storm, data for the following weather types as defined by the National Weather Service (NWS) Raleigh Forecast Office and tracked by NCEI were collected: • Blizzard – A winter storm which produces the following conditions for 3 consecutive hours or longer: (1) sustained winds or frequent gusts 30 knots (35 mph) or greater, and (2) falling and/or blowing snow reducing visibility frequently to less than 1/4 mile. • Cold/Wind Chill – Period of low temperatures or wind chill temperatures reaching or exceeding locally/regionally defined advisory conditions of 0°F to -14°F with wind speeds 10 mph (9 kt) or greater.
• Extreme Cold/Wind Chill – A period of extremely low temperatures or wind chill temperatures
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 209
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