SECTION 4: RISK ASSESSMENT
Extreme Cold/Wind Chill – A period of extremely low temperatures or wind chill temperatures reaching or exceeding locally/regionally defined warning criteria, defined as wind chill -15°F or lower with wind speeds 10 mph (9 kt) or greater. Frost/Freeze – A surface air temperature of 32°F or lower, or the formation of ice crystals on the ground or other surfaces, for a period of time long enough to cause human or economic impact, during the locally defined growing season. Heavy Snow – Snow accumulation meeting or exceeding 12 and/or 24 hour warning criteria of 3 and 4 inches, respectively. Ice Storm – Ice accretion meeting or exceeding locally/regionally defined warning criteria of ¼ inch or greater resulting in significant, widespread power outages, tree damage and dangerous travel. Issued only in those rare instances where just heavy freezing rain is expected and there will be no "mixed bag" precipitation meaning no snow, sleet or rain. Sleet – Sleet accumulations meeting or exceeding locally/regionally defined warning criteria of ½ inch or more. Winter Storm – A winter weather event that has more than one significant hazard and meets or exceeds locally/regionally defined 12 and/or 24 hour warning criteria for at least one of the precipitation elements. Defined by NWS Raleigh Forecast Office as snow accumulations 3 inches or greater in 12 hours (4 inches or more in 24 hours); Freezing rain accumulations ¼ inch (6 mm) or greater; Sleet accumulations ½ inch (13 mm) or more. Issued when there is at least a 60% forecast confidence of any one of the three criteria being met. Winter Weather – A winter precipitation event that causes a death, injury, or a significant impact to commerce or transportation, but does not meet locally/regionally defined warning criteria. Summarized impacts from data collected for 1998 through 2017 are included in Table 4.68. Cumulatively, severe winter storms caused over $1 million in property damage. In this timeframe, the county experienced no fatalities, injuries or crop damage from severe winter storm, though these types of impacts are possible in future events. No blizzard, cold/wind chill, extreme cold/wind chill, frost/freeze, or sleet events were recorded. Impacts in Wake County by incident are recorded in Table 4.69. Table 4.68 – Total Severe Winter Storm Impacts in Wake County, 1998-2017
Number of Recorded Incidents
Total Fatalities
Total Injuries
Total Property Damage
Total Crop Damage
Event Type
Winter Storm
25
0 0 0 0 0
0 0 0 0 0
$1,000,000
$0 $0 $0 $0 $0
Winter Weather 19
$40,000
Ice Storm
1 1
0 0
Heavy Snow
Total
46
$1,040,000
Source: NCEI
Table 4.69 – Recorded Severe Winter Storm Impacts in Wake County, 1998-2017
Date
Event Type Heavy Snow
Fatalities
Injuries
Property Damage
Crop Damage
1/19/1998 12/23/1998 1/18/2000 1/20/2000 1/22/2000 1/24/2000 1/28/2000
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
Ice Storm
Winter Storm Winter Storm Winter Storm Winter Storm Winter Storm
Wake County Multi-Jurisdictional Hazard Mitigation Plan 2019
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