May is peak time for tornadoes, usually bringing about 270. This stretch alone - with at least 225 tornadoes - will likely come close to that figure as the counts are finalised.
According to various stats, the current run is about as active for as long a period as seen in the modern record since 1950.
It is the most active since the hyperactive season in 2011 that included notable events such as a major outbreak in April and the Joplin, Missouri, catastrophe the next month.
After filtering out the weakest tornadoes, tallies for this stretch are among the top four years on record for the second half of May.
This streak is near records for the lengthiest streaks of days with five or more EF1-plus tornadoes. The EF scale measures intensity of tornadoes, with EF0 being least significant and EF5 being most.
Harold Brooks, a tornado scientist at NOAA's National Severe Storms Laboratory, recently tweeted the numbers. In 1980, an 11-day run began on May 28. The most recent lengthy streak was during the longest outbreak sequence on record in May 2003, when seven consecutive days occurred.
Per early stats, this stretch has seen at least an eight-day stretch, which would tie for the second-longest on record. May 25 falls just short with four confirmed EF1 or greater tornadoes, but shifting numbers may mean the record longest streak is still in play here.
The tornadoes have been striking communities, often after sunset. Night-time tornadoes hit Golden City, Missouri, where the deadliest storm killed three people; Jefferson City, Missouri; Dayton; and El Reno, Oklahoma.
May is peak tornado season, but an extraordinary and persistent pattern has kept conditions conducive for tornadoes on a longer-than-average span.
A primary cause in this case is a series of large low pressure systems that have repeatedly moved through the West Coast - delivering chilly and wet weather to the region. As low pressure systems leave the Rockies, they have spawned tornadoes across the Central and Eastern US.
Such a weather pattern has been unusually persistent in part due to high pressure blocking in the northern latitudes. High pressure has been locked near Alaska since winter, and one over Greenland also intensified. This configuration helped lock low pressure and cold air into the West as high pressure and warm air dominate the East.
This run of twisters also at least loosely fits into the idea that more tornadoes are arriving on fewer days in recent history, although this stretch does have some precedent and similar activity seems to happen, on average, about once every decade or two.
