Johnson County Natural Disasters and Weather Extremes
The chance of earthquake damage in Johnson County is lower than Tennessee average and is much lower than the national average. The risk of tornado damage in Johnson County is much lower than Tennessee average and is much lower than the national average.
Earthquake Index, #31
| Johnson County | 0.31 |
| Tennessee | 0.56 |
| U.S. | 1.81 |
The earthquake index value is calculated based on historical earthquake events data using USA.com algorithms. It is an indicator of the earthquake level in a region. A higher earthquake index value means a higher chance of an earthquake.
Volcano Index, #1
| Johnson County | 0.0000 |
| Tennessee | 0.0000 |
| U.S. | 0.0023 |
The volcano index value is calculated based on the currently known volcanoes using USA.com algorithms. It is an indicator of the possibility of a region being affected by a possible volcano eruption. A higher volcano index value means a higher chance of being affected.
Tornado Index, #82
| Johnson County | 30.34 |
| Tennessee | 175.35 |
| U.S. | 136.45 |
The tornado index value is calculated based on historical tornado events data using USA.com algorithms. It is an indicator of the tornado level in a region. A higher tornado index value means a higher chance of tornado events.
Other Weather Extremes Events
A total of 14,030 other weather extremes events within 50 miles of Johnson County were recorded from 1950 to 2010. The following is a break down of these events:
| Type | Count | Type | Count | Type | Count | Type | Count | Type | Count |
| Avalanche: | 0 | Blizzard: | 1 | Cold: | 64 | Dense Fog: | 5 | Drought: | 86 |
| Dust Storm: | 0 | Flood: | 1,610 | Hail: | 3,935 | Heat: | 30 | Heavy Snow: | 317 |
| High Surf: | 0 | Hurricane: | 13 | Ice Storm: | 70 | Landslide: | 4 | Strong Wind: | 205 |
| Thunderstorm Winds: | 6,763 | Tropical Storm: | 13 | Wildfire: | 25 | Winter Storm: | 159 | Winter Weather: | 143 |
| Other: | 587 | ||||||||
Volcanos Nearby
No volcano is found in or near Johnson County.
Historical Earthquake Events
No historical earthquake events that had recorded magnitudes of 3.5 or above found in or near Johnson County.
No historical earthquake events found in or near Johnson County.
Historical Tornado Events
A total of 14 historical tornado events that had recorded magnitude of 2 or above found in or near Johnson County.
| Distance (miles) | Date | Magnitude | Start Lat/Log | End Lat/Log | Length | Width | Fatalities | Injuries | Property Damage | Crop Damage | Affected County |
| 19.1 | 1965-04-09 | 2 | 36°11'N / 81°56'W | 0.50 Mile | 300 Yards | 0 | 1 | 25K | 0 | Avery | |
| 21.4 | 1962-06-03 | 2 | 36°36'N / 82°12'W | 0 | 0 | 25K | 0 | Washington | |||
| 23.6 | 1975-01-25 | 2 | 36°47'N / 81°46'W | 36°47'N / 81°44'W | 1.30 Miles | 30 Yards | 0 | 0 | 25K | 0 | Washington |
| 24.7 | 1975-01-25 | 2 | 36°47'N / 81°44'W | 36°48'N / 81°42'W | 1.90 Miles | 30 Yards | 0 | 2 | 25K | 0 | Smyth |
| 28.0 | 1974-04-04 | 3 | 36°51'N / 81°55'W | 36°52'N / 81°49'W | 5.40 Miles | 177 Yards | 1 | 1 | 250K | 0 | Washington |
| 29.4 | 1974-04-04 | 3 | 36°52'N / 81°49'W | 36°53'N / 81°46'W | 3.00 Miles | 177 Yards | 0 | 3 | 250K | 0 | Smyth |
| 33.5 | 2009-05-08 | 2 | 36°56'N / 81°57'W | 1.00 Mile | 250 Yards | 0 | 0 | 0K | 0K | Russell | |
| Brief Description: EVENT NARRATIVE: A tornado touched down about eight miles east-northeast of Lebanon, Virginia with maximum wind speeds of 125 miles an hour. The path length was 1.1 mile and maximum width was 250 yards. Approximately 100 trees were snapped and uprooted along the tornado path. In addition...a well constructed wooden barn was completely destroyed and while a home incurred moderate damage. EPISODE NARRATIVE: A highly organized mesoscale convective vorticity maximum with strong low to mid tropospheric flow coupled with moderate instability resulted in the development of discrete supercellular thunderstorms. These storms produced a long-lived tornado across Northeast Tennessee late in the afternoon and another long duration tornado across Southwest Virginia later in the evening. | |||||||||||
| 36.8 | 1989-05-05 | 2 | 35°57'N / 81°41'W | 36°01'N / 81°25'W | 15.00 Miles | 73 Yards | 0 | 0 | 250K | 0 | Caldwell |
| 40.6 | 1957-04-08 | 2 | 36°17'N / 82°35'W | 36°19'N / 82°33'W | 3.00 Miles | 440 Yards | 0 | 0 | 3K | 0 | Washington |
| 47.0 | 1974-04-04 | 2 | 35°49'N / 81°32'W | 35°52'N / 81°27'W | 5.70 Miles | 33 Yards | 0 | 0 | 250K | 0 | Caldwell |
| 48.6 | 2009-05-08 | 2 | 36°33'N / 81°02'W | 36°32'N / 80°57'W | 5.00 Miles | 200 Yards | 0 | 6 | 200K | 0K | Alleghany |
| Brief Description: EVENT NARRATIVE: A low end EF-2 tornado touched down on Osee Road and was intermittently on the ground approximately 5 miles moving east-southeast, finally lifting between Old Barrett Road and Glade Valley Road. A single wide mobile home was destroyed on Osee Road, causing four injuries. Along the track, cement silos were collapsed, 5 other homes were damaged, and several other structures were heavily damaged. Two people received minor injuries when struck by debris after winds blew out windows in their home. Monetary damages are estimates. EPISODE NARRATIVE: A thunderstorm complex over Kentucky and Tennessee moved east into the area during the evening of May 8th. The storm environment was such that storms would have rotation due to strong wind shear, and a low level boundary in place. Supercells developed over southeast Kentucky and moved southeast into far southwest Virginia and into northwest North Carolina during the late evening of May 8th. One storm produced an EF-2 tornado in Northern Alleghany County, with another brief EF-1 tornado touching down just south of the EF-2 track. | |||||||||||
| 49.0 | 1967-04-22 | 2 | 36°12'N / 82°41'W | 0.20 Mile | 250 Yards | 0 | 0 | 250K | 0 | Greene | |
| 49.5 | 1998-05-07 | 4 | 35°52'N / 81°23'W | 35°52'N / 81°19'W | 4.00 Miles | 1320 Yards | 0 | 2 | 1.1M | 0 | Caldwell |
| Brief Description: A violent, F4 tornado touched down near Dudley Shoals then moved east-southeast cutting a winding path through valleys, to the Alexander county border. The damage path was 100 yards wide on average, but reached a width of 3/4 of a mile at times. One well-constructed home was totally destroyed, other homes were damaged, and many mobile homes sustained damage or were destroyed. Supercell thunderstorms developed in a highly sheared atmosphere in eastern Tennessee then moved east across the mountains, foothills and western piedmont of North Carolina. These long-lived, cyclic supercells produced a considerable amount of large hail and some damaging winds in the mountains. The first tornado of the day in western North Carolina occurred in Madison county. Numerous reports of hail as large as golf balls were reported from the mountains. In Madison and Yancey counties, hail covered roads. More supercell thunderstorms developed behind the previous ones and followed similar tracks. In northern Buncombe county, the town of Barnardsville had three separate severe storms cross overhead and drop hail on the ground to a depth of 3 inches. Yancey county also had 3 separate storms move across the county that accumulated hail to 6 inches in depth. The hail was still on the ground the next morning. As the supercells moved into the foothills, they began to curve a little to the right, indicative of strong mesocyclonic circulations present. One supercell produced several tornadoes from Alexander county to Davie county. Another storm produced a tornado that tracked from western Caldwell county into south-central Alexander county. A third supercell that emerged out of the mountains in McDowell county produced several tornadoes from the southern part of that county to northern Mecklenburg county. Damage was fairly significant across western North Carolina with numerous homes either damaged or destroyed. Fortunately, no one was killed. However, 2 people were injured as a result of the violent F4 tornado in eastern Caldwell county. One person received minor injuries from a lightning strike in Yancey county later in the evening. The storms continued to reform in eastern Tennessee until very late in the evening and still produced large hail as they crossed the border into the mountain counties of North Carolina, before weakening shortly after midnight.. | |||||||||||
| 49.8 | 1979-05-24 | 2 | 35°45'N / 81°40'W | 0.30 Mile | 30 Yards | 0 | 0 | 250K | 0 | Burke | |
* The information on this page is based on the global volcano database, the U.S. earthquake database of 1638-1985, and the U.S. Tornado and Weather Extremes database of 1950-2010.