Lake Wheeler


Map of Tornado Risk Across U.S. A tornado is a column of violently rotating air, spawned by a thunderstorm, which is connected from the thunderstorm cloud to the ground. It often appears funnel shaped or as a column of debris. Tornadoes are one of nature's most violent storms. They may develop suddenly, and may contain winds that reach over 250 mph. Tornadoes are a threat to human life and responsible for millions of dollars worth of property damage each year in North Carolina.

In 1971, Dr. Theodore Fujita developed a scale to categorize tornadoes based upon their intensity and area. This scale is known as the Fujita Scale, which relates a tornado's damage to the fastest quarter-mile wind speed at the height of a damaged structure to determine intensity. Over the years, problems have arisen with this scale. For starters, the scale is solely based upon the damage caused by a tornado, which makes it difficult to determine intensity if the tornado moves over an area with no structures. In addition, the scale does not take into account differences between structures based upon how they are constructed. To account for some of these problems, a modified version of this scale known as the Enhanced Fujita Scale was created and put into operation in 2007.

Fujita Scale vs. Enhanced Fujita Scale

Fujita Scale Enhanced Fujita Scale
F-Scale Fastest 1/4 Mile Wind Speed 3-Second Wind Gusts Type of Damage Done EF-Scale 3-Second Wind Gusts
F0 (Gale) 40 - 72 mph 45 - 78 mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards EF-0 65 - 85 mph
F1 (Weak) 73 - 112 mph 79 - 117 mph Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off roads EF-1 86 - 110 mph
F2 (Strong) 113 - 157 mph 118 - 161 mph Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated EF-2 111 - 135 mph
F3 (Severe) 158 - 207 mph 162 - 209 mph Roof and some walls torn off well constructed houses; trains overturned; most trees in forests uprooted EF-3 136 - 165 mph
F4 (Devastating) 208 - 260 mph 210 - 261 mph Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated EF-4 166 - 200 mph
F5 (Incredible) 261 - 318 mph 262 - 317 mph Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel reinforced concrete structures badly damaged EF-5 > 200 mph

Enhanced Fujita Scale Damage Indicators

Number Damage Indicator Number Damage Indicator
1 Small barns, farm outbuildings 15 1-story elementary school
2 One- or two-family residences 16 Junior or senior high school
3 Single-wide mobile home 17 Low-rise building (1-4 stories)
4 Double-wide mobile home 18 Med-rise building (5-20 stories)
5 Apartment, condo, townhouse (3 stories or less) 19 High-rise building (> 20 stories)
6 Motel 20 Institutional building (i.e. hospital, government, university)
7 Masonry apartment or motel 21 Metal building system
8 Small retail building (i.e. fast food) 22 Service station canopy
9 Small professional building (i.e. doctor office, branch bank) 23 Warehouse (tilt-up walls or heavy timber)
10 Strip mall 24 Transmission line tower
11 Large shopping mall 25 Free-standing tower
12 Large, isolated retail building 26 Free-standing pole (i.e. light, flag, luminary)
13 Automobile showroom 27 Tree (hardwood)
14 Automotive service building 28 Tree (softwood)

For more information regarding the enhanced scale, click here.

An analysis of the climatology of tornadoes in North Carolina for a period of fifty years (1950-1999) is performed using tornado data obtained from the National Climatic Data Center (NCDC) and the National Severe Storms Laboratory (NSSL). The data is examined spatially using a Geographic Information System (GIS) to illustrate tornado patterns across the state. The data is also examined to find evidence of significant trends in tornado occurrences on a geographic scale, time scale, and with relation to population. Analysis suggests that there is an increasing trend in tornado occurrences, tornado days, tornado deaths, and tornado injuries. Analysis also suggests that more tornadoes occur in the southeast and southcentral regions of North Carolina.

Below are a series of charts and maps that summarize the climatology of tornadoes in North Carolina:

  • Tornado occurrences, tornado days, tornado deaths, and tornado injuries are increasing
  • Most tornado occurrences are of F0 and F1 intensity, however, most tornado injuries and deaths are results of more significant tornadoes
  • Most reported tornado occurrences are in southeastern and southcentral North Carolina
  • The majority of the intense tornadoes occur in central North Carolina
  • The majority of tornado fatalities are the result of a single storm

Tornado Locations and Intensities per County Count of Observed Tornadoes per County Tornado Injuries per County Count of Injury-Causing Tornadoes per County Number of Tornado Fatalities per County Count of Deadly Tornades per County Number of Observed NC Tornadoes per Year Observed Tornadoes versus Number of Days with Tornadoes Number of Tornadoes per Decade Number of Tornadoes per Fujita Scale Number of Injuries per Tornado Intensity Number of Fatalities per Tornado Intensity Fatalities and Injuries versus Observed Tornadoes