A high risk is the most serious category on the Storm Prediction Center's scale measuring the threat for severe weather on a given day. High risks are reserved for potential tornado outbreaks or derechos, which are long-lived squall lines that produce extensive wind damage along a path stretching for hundreds of miles.

Forecasters at the SPC don't issue high risks lightly. It's tough for the ingredients to come together just right for a major severe weather outbreak to unfold. High risks convey high confidence in a high-impact weather event.

While some of the worst tornadoes in modern history have occurred on high-risk days, it's important to remember that the vast majority of destructive tornadoes and tornado-related injuries and deaths occur on days without a high risk in place. All severe weather is dangerous.

The most recent high risk issued by the Storm Prediction Center appeared during a severe weather outbreak on Saturday, March 15, 2025.

The high risk area covered portions of Alabama and Mississippi. Forecasters issued the high risk one day in advance for only the third time since 2006. A powerful low-pressure system over the central U.S. created favorable dynamics for a tornado outbreak in and around the high risk area.

Multiple tornadoes were reported in the moderate risk and high risk areas. Convection quickly muddied the atmosphere in the high risk area, though, preventing many discrete supercells from developing and taking full advantage of the environment.

This was the 66th day since January 1, 2000, that the SPC has issued a high risk somewhere in the United States.

There were 224 same-day high risk outlooks issued by the Storm Prediction Center between January 1, 2000, and December 31, 2024, accounting for 65 days over the past two-and-a-half decades. The SPC issues multiple forecast updates throughout the day—this map counts all of those updates.

All of the high risks were issued east of the Rocky Mountains, and the vast majority covered traditional Tornado Alley in the central U.S., as well as portions of Mississippi and Alabama.

The coverage of high risk outlooks since 2000 stands in as a solid climatology for which areas of the country are prone to some of the most extreme severe thunderstorms during the spring and summer months. Only a few areas have seen a single high risk; this includes Virginia Beach (April 16, 2011) and Tampa, Florida (January 22, 2017).

Communities on the central Plains and throughout the Mississippi Valley have witnessed 20-30 high risk areas since the turn of the milennium, with some areas seeing more than 30 individual high risk outlooks.

The maximum number of high-risk overlaps since 2000 appears in northeastern Mississippi, just southwest of Tupelo. These rural communities have fallen under 41 separate high risk outlooks, mostly driven by tornado outbreaks.

Some of the dates below link out to pages that describe each high-risk day in more detail.