The number of tornadoes a year has not changed but researches have noticed a pattern change in tornadoes. In the past, tornadoes had lone occurrences but now they are coming in packs. Researchers are unable to explain why this change is occurring. These clusters or outbreak of tornadoes is defined as six or more tornadoes. Tornadoes that have twelve or more tornadoes in close succession is considered an extreme outbreak. The average number of tornado extreme outbreaks was around 80 in 2015 compared to only 40 in 1965. The largest recorded outbreak in a 24 hour period was over 200 tornadoes which occurred on April 27, 2011. They have recently linked the intensity of those tornadoes to the smoke from wildfires but there are also many other factors
