SECTION 4: RISK ASSESSMENT
• Excessive Heat Warning – Heat Index values 110°F or higher for 2 hours or more
Based on data from the “Raleigh State Univ” weather station from January 1892 through January 2024, the highest temperature recorded in Wake County was 107°F and occurred in July 2011.
Impact: 3 – Critical
Spatial Extent: 4 – Large HISTORICAL OCCURRENCES
According to the National Oceanic and Atmospheric Administration (NOAA), 2020 was North Carolina’s hottest year on record with an average of 61.7 degrees Fahrenheit; that record stretches back 128 years to 1895. The following two heat-related incidents were reported by NCEI for Wake County; these incidents caused one injury and no fatalities, property damage, or crop damage: July 22, 1998 – Excessive heat plagued central North Carolina during July 22 through July 23. Maximum temperatures reached the 98 to 103 degree range combined with dew points in the 78 to 80 degree range with little wind to give heat index values of around 110 degrees for several hours each afternoon. To make matters worse, the minimum temperatures did not fall below 80 at several locations and those that did achieved that feat for only an hour or two. Strong thunderstorms ended the 2 day excessive heat ordeal on the evening of the 23 when rain cooled the environment enough to send temperatures into the lower 70s at most locations. August 22, 2007 – An athlete from Enloe High School running track collapsed from heat exhaustion and was sent to the hospital in critical condition. The student remained in the hospital in critical condition for several days. PROBABILITY OF FUTURE OCCURRENCE Data was gathered from the North Carolina State Climate Office’s Climate Thresholds Tool using the Raleigh State University weather station as an approximation for Wake County. During the 25-year period from 1998 through 2023, Wake County experienced 49 days with a high temperature greater than or equal to 100°F, or an average of 1.9 days per year. In 2012, there were 10 days with recorded temperatures above this threshold.
Probability: 4 – Highly Likely CLIMATE CHANGE
Research shows that average temperatures will continue to rise in the Southeast United States and globally, directly affecting the Wake County region in North Carolina. Per the Fifth National Climate Assessment, “ The number of extreme warm days (above 95°F) is expected to continue increasing with every increment of global warming.” Additional heat stresses can be attributed to the urban heat island effect which can increase the temperature of those living in urban environments compared to rural areas. The number of days over 95°F is expected to increase by between 20 and 30 days annually, as shown in Figure 4.17. The Triangle Regional Resilience Partnership Resilience Assessment notes that the number of days with extreme temperatures has been increasing in the Triangle; climbing from an average of 18 days over 92°F per year from 1948 to 2012 to a peak of 48 days over 92°F in 2010.
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 121
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