Progression of a well-anticipated high risk event across the Central Plains on April 14, 2012. This event ultimately produced 85 tornadoes that day, one of which killed six people.
A high risk severe weather event is the greatest threat level issued by the Storm Prediction Center (SPC) for convective weather events in the United States. On the scale from one to five, a high risk is a level five; thus, high risks are issued only when forecasters at the SPC are confident of a major severe weather outbreak. This is usually for major tornado outbreaks with numerous strong to violent tornadoes expected, and occasionally derechos with widespread destructive wind gusts, and these outlooks are typically reserved for the most extreme events.[1] They are generally only issued on the day of the event. However, there have been two occurrences (April 7, 2006, and April 14, 2012) of a high risk being issued for Day 2 of the outlook period (with the event occurring the following day). Under the official protocol, a high risk cannot be issued for Day 3 of the outlook period.[2]
High risk days
1982–1989
Thirty-four high risks were issued in the 1980s.
1990–1999
Sixty high risks were issued in the 1990s.
2000–2009
There were no high risk days in 2000.
2010–2019
There were no high risk days in 2015, 2016, or 2018.
^ a b c d eAll values include events that took place outside the high-risk area(s). Tornado and fatality totals only include incidents that occurred on the respective high risk days. Fatality totals only include direct tornadic deaths.
^Starting on February 1, 2007, the Fujita Scale was replaced with the Enhanced Fujita Scale for rating tornadoes.
^This number reflects the number of tornadoes during the outlook period between 12Z on the day of the high risk to 12Z the next day.
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