According to data from NOAA's Storm Prediction Center, during March, there were 1,376 preliminary tornado reports. This was above the 1991-2010 U.S. annual average of 1,251 tornadoes. The most prolific months during 2021 for tornadoes were March, May, July and December, as each of these months reported 150 or more tornadoes. Specific event days that had the highest tornado frequency and impacts are summarized below.
On March 13, there were 27 tornadoes that were clustered in the Texas Panhandle. All of these were EF-2, EF-1 or EF-0 tornadoes that caused damage to homes, businesses and vehicles. There were no tornado-related fatalities. On March 17, there were 56 tornadoes that impacted several states including Mississippi, Alabama, Georgia, Florida, Arkansas and Missouri. The majority of these tornadoes were EF-1 or EF-0 with several EF-2 tornadoes in Mississippi and Alabama. These tornadoes caused widespread damage to homes, businesses and vehicles. There were no tornado-related fatalities. On March 25, there were 41 tornadoes that impacted several states including Kentucky, Tennessee, Mississippi, Alabama and Georgia. These included one EF-4, four EF-3s, ten EF-2s and approximately two-dozen EF-1 or EF-0 tornadoes. The strongest of these tornadoes were focused across central Alabama and western Georgia with tracks across the entire width of Alabama. There was widespread damage to homes, businesses, vehicles and infrastructure. There were also 5 fatalities in Alabama. On March 27, there were 26 tornadoes that impacted several states including Texas, Arkansas, Mississippi, Tennessee and Illinois. Six of these tornadoes were EF-2, but the majority were weaker EF-1 or EF-0 tornadoes. These tornadoes produced damage to a number of homes, businesses and vehicles. There were two fatalities.
According to data from NOAA's Storm Prediction Center, during May, there were 288 preliminary tornado reports. This is near the 1991-2010 average of 276 tornadoes for the month of May. Historically, the month of May represents the peak of the U.S. tornado season, as it has the highest average number of tornadoes per month based on the 1991-2010 reference period. May was an active month for tornadoes with at least one tornado reported on 25 separate days during the month. The May tornado count escalated quickly at the beginning of the month, as at least 96 confirmed tornadoes occurred on May 2-4. However, there were no EF-3+ tornadoes reported across the CONUS during May. If this verifies, it will be the first time, since reliable records began in 1950, that no EF-3+ tornadoes occurred during the month of May. The month also had no tornado-related deaths, which is the first May without a tornado death since 2014. The days with the highest count of tornadoes and notable impacts are noted below in chronological order.
On May 2-4, there were at least 96 tornadoes that developed across several southeastern states. On May 2, there were dozens of tornadoes that formed along a southwest to northeast track through central Mississippi. These tornadoes produced damage to homes, vehicles and infrastrucutre, but there were no tornado-related fatalities. May 3 and 4 produced numerous tornadoes along the Tennessee and Kentucky border and another cluster of tornadoes formed across northern Georgia into South Carolina. The strongest tornado occurred on May 3 in Greenwood, SC and was rated an EF-2 with winds of 125 mph. Another tornado rated EF-1, with winds of 110 mph occurred in York County, SC, causing major damage at a family farm killing thousands of turkeys. There were also many isolated tornadoes in other states including Texas, Arkansas, Illinois, Pennsylvania, Maryland and Virginia. In total, this three-day event produced six EF-2, 35 EF-1 and 38 EF-0 tornadoes that collectively caused damage to homes, businesses and vehicles. There were also numerous weaker tornadoes of unknown or not-classified (EF-U) that were part of this storm system. Also, despite the larger number of tornadoes during this three-day event there were reported injuries but no tornado-related fatalities.
On May 16-19, there were 51 tornadoes that were scattered across numerous states including Colorado, Wyoming, Kansas, New Mexico, Texas, Arkansas, Louisiana, Mississippi, South Dakota and Minnesota. The majority of these tornadoes were EF-1 or EF-0 with numerous EF-U tornadoes that were clustered in Louisiana and Minnesota on May 17 and 19, respectively. These tornadoes caused mostly minor damage to homes, vegetation and infrastructure. On May 22-24, there were 39 tornadoes that impacted Colorado, South Dakota and Kansas. These were all weaker tornadoes that occurred over rural areas, which limited their impact, causing minor damage to vegetation and infrastructure. There was one reported injury but no tornado-related fatalities. On May 26, there were 28 tornadoes that impacted Nebraska, Kansas, Oklahoma and Texas. The majority of the tornadoes formed along a line from southwestern Nebraska into central Kansas. These were all weaker tornadoes that caused mostly minor damage to farmsteads, homes and other infrastructure. On May 30, there were 13 tornadoes that impacted Colorado, New Mexico, Oklahoma and Texas. These were all tornadoes that occurred over rural areas, which limited their impact and are all rated as EF-U. These tornadoes did cause minor damage to vegetation and infrastructure.
On July 14, there was an outbreak of 38 tornadoes that occurred across Iowa. This outbreak produced a combination of EF-2, EF-1 and EF-0 tornadoes, as well as one EF-3 tornado. The EF-3 tornado passed through Lake City and produced damage to homes, farmsteads, vegetation and other infrastructure. This one-day outbreak across Iowa was one of Iowa's most prolific tornado-producing days in decades. There were no tornado-related fatalities. The highest tornado count for any two-day period was on July 28-29, as 50 tornadoes were reported across Wisconsin, Illinois, Indiana, Ohio, Pennsylvania and New Jersey. A majority were EF-1 and EF-0 tornadoes, but there were also at least four EF-2 and one EF-3 tornado. The EF-3 tornado caused major damage across the northeastern suburbs of Philadelphia, as homes, businesses, vehicles and other infrastructure were damaged. In particular, several automotive dealerships sustained extensive damage to the many vehicles and surrounding buildings. Other large retail complexes also sustained minor to moderate levels of damage. This was the first EF-3 tornado in Pennsylvania since 2004. There were at least 5 injuries but no tornado-related fatalities.
September 1 produced numerous tornadoes that caused severe damage across parts of the northeast from the remnants of Hurricane Ida merged with a frontal boundary. New Jersey, New York, Connecticut, Massachusetts Pennsylvania and Maryland were all impacted by Ida-enhanced storms that produced tornadoes. The most severe damage was in Cedar Grove and Mullica Hill, New Jersey where many homes sustained significant damage. Walls and roofs on well-anchored houses received heavy damage. Numerous vehicles were also damaged or destroyed. Residential subdivisions, a commercial farm and other infrastructure was impacted from one wedge tornado that was rated an EF-3. This was the first F3 or EF3 rated tornado in New Jersey since 1990. There were no fatalities from this EF-3 tornado. However, on September 1, another rain-wrapped EF-2 tornado in Montgomery County, Pennsylvania did cause one fatality. In total on September 1 across the northeastern states, the tornadoes were rated as: one EF-3, three EF-2, three EF-1 and three EF-0.
On October 9-13, there were 64 tornadoes that developed across several north-central and central states. On October 9, there were eight tornadoes that formed in Minnesota, South Dakota and North Dakota. These tornadoes produced damage to homes, vehicles, farms and an industrial park, but there were no tornado-related fatalities. On October 10, Oklahoma experienced a nearly continuous line of severe storms that produced 16 tornadoes bisecting the state from the southwest to the northeast. There was EF-2 damage in Anadarko, Oklahoma, in which numerous structures were damaged or destroyed including homes, barns and vehicles. There was also an isolated EF-2 tornado in East Cook, Minnesota that crossed Mountain Lake into Canada. There were no fatalities with any of the October 10 tornadoes. On October 11, there were 11 tornadoes across central Illinois including an EF-2 in Wrights, Illinois that destroyed several farmsteads, homes and vehicles. October 12-13, there were a combined 27 EF-0, EF-1 and EF-U tornadoes across Oklahoma, Kansas, Nebraska, Minnesota, North Dakota and South Dakota. These tornadoes produced scattered damage to homes, farms, vegetation and infrastructure and there were no fatalities.
Another high-impact day was October 21, in which there were 18 tornadoes across eastern Ohio and western Pennsylvania. This included an EF-2 tornado that caused significant damage destroying homes, vehicles, farms and vegetation, as it moved through Buffalo Township, Pennsylvania. All of the other tornadoes on October 21 were EF-0 or EF-1 producing scattered damage and no fatalities. October 24 was another active day that produced 23 tornadoes across Missouri and Illinois. There were two destructive EF-3 tornadoes during this day. The first was a long-track EF-3 that impacted several towns beginning south of Farmington, Missouri to Breman, Illinois. There was a tornado emergency issued while this tornado crossed the Mississippi River into Illinois before impacting the town of Chester, Missouri. This tornado produced damage to homes, businesses, vehicles, farms and other infrastruture. A second EF-3 tornado impacted several towns beginning west of Fredericktown, Missouri to Junction City, Missouri. This tornado also caused considerable destruction to homes, warehouses, vehicles, farms and other infrastruture. At least 6 injuries were reported, but no fatalities were associated with this event.
December 10 produced a historic December tornado outbreak across several southeast and central states caused devastating damage across many towns and cities. This outbreak produced two long-tracked EF-4 tornadoes across Arkansas, Missouri, Tennessee and Kentucky. The longest tornado track was nearly 166 miles across Kentucky and a small portion of Tennessee. This was the longest-tracked tornado on record in Kentucky and was a U.S. record tornado track length for the month of December. There were over 800 total miles of tornado path length on December 10. The peak intensity from this outbreak was EF-4 rated wind speeds of 190 mph in Mayfield, Kentucky. Mayfield's downtown district was heavily damaged. This day was also the deadliest December tornado outbreak (93 direct and indirect fatalities) recorded in the United States surpassing the Vicksburg, Mississippi tornado of December 5, 1953, which caused 38 fatalities. There were also many more people that sustained injuries from this outbreak of torandoes.
On December 15 there was another record-breaking December tornado outbreak that caused widespread damage and was focused across Kansas, Nebraska, Iowa, Minnesota and Wisconsin. There were many reports of hurricane-force thunderstorm wind gusts and more than 50 tornadoes causing widespread damage to homes, vehicles, businesses and infrastructure. This was the first December derecho on record to occur within the United States. This event also produced the first December tornado on record in Minnesota since 1950, with 20 tornadoes reported across southeast Minnesota.
Did You Know?
Final monthly tornado counts are typically less than the preliminary count. This can be due to some phenomena being inaccurately reported as tornadic activity or a single tornado being reported multiple times. Tornado accounts are reported to the local National Weather Service forecast offices who are responsible for going into the field and verifying each tornado reported. This process often takes several months to complete. Once all reports have been investigated, the final count is published by the Storm Prediction Center (SPC).
The Tornado Monthly Climate Reports are written using the preliminary numbers because the final data is not available at the time of production. Historically, for every 100 preliminary tornado reports, at least 65 tornadoes are confirmed. An error bar is depicted on the tornado count graphic representing this uncertainty in the preliminary tornado count.
The following U.S. studies performed by SPC meteorologists offer deeper context and discussion regarding the frequency and distribution of tornado intensity climatologies:
- Edwards, R., H. E. Brooks, and H. Cohn, 2021: Changes in tornado climatology accompanying the Enhanced Fujita scale. J. Appl. Meteor. Climatol., 60, 1465-1482, DOI: 10.1175/JAMC-D-21-0058.1.
- Mccarthy, Daniel & Schaefer, Joseph. (2004). Tornado trends over the past thirty years. paper presented at 14th Conference on Applied Meteorology.