Tornado Warnings Should All Be Taken Seriously, But There Are Different Types You Should Know About

Critical Difference Between Tornado Warnings

When a tornado warning is issued you should always take it seriously and seek shelter, but there are multiple types to know about that can help you understand more about this urgent situation.

Big Picture: What Prompts A Tornado Warning

A tornado warning is issued by the National Weather Service when a tornado has been sighted and/or indicated by radar. What you might not have noticed before is that each tornado warning tells you the specific reason it was issued.

Next, we'll take a deeper dive into the terminology you should look for and what it means.

(MORE: What Makes A Storm Severe)

Most Common Type: Warnings Prompted By Rotation

Most tornado warnings cite "radar indicated rotation" as the reason the warning was issued.

That means a severe thunderstorm is exhibiting signs of strong rotation on Doppler radar, which indicates that a tornado could be in progress or that one could form at any time.

When "radar indicated rotation" is cited in the warning, it's not yet known if an actual tornado is in progress, but the NWS forecaster wants to provide as much lead time as possible before a tornado occurs to keep you safe.

(MORE: Tornado Watch Vs. Warning)

Second Type: Warnings For Confirmed Tornadoes

A tornado can be confirmed as in progress in two different ways, both of which you will see stated in warnings.

• Radar Confirmed Tornado: This will appear in the text of some warnings that are issued based on radar. It means Doppler radar is showing signs that debris has been lofted into the air near the area of low-level rotation in a storm, giving the NWS high confidence a tornado is in progress.

• Spotter Confirmed Tornado: On occasion, you will see "confirmed tornado from trained spotters" as the source cited in a tornado warning. That means a tornado has been spotted by a trained spotter and/or law enforcement.
• Particularly Dangerous Situation Confirmed Tornadoes: You might see this line in warnings for radar confirmed or spotter confirmed tornadoes that are likely to be strong. These warnings are a heightened version of a tornado warning that is meant to suggest an unusually high threat of damage and loss of life exists for a particular storm. PDS tornado warnings are uncommon.

Rarest Type: Emergency Warning

Tornado warning text that carries with it a "tornado emergency" is the rarest and is reserved for the most dire situations.

This is only issued "when there is a severe threat to human life and catastrophic damage from an imminent or ongoing tornado", the NWS says.

A tornado emergency can be issued based on a confirmed sighting of a tornado or one that has been confirmed by radar.

The first tornado emergency was issued by the NWS-Norman, Oklahoma, office during the May 3, 1999 outbreak. It was for a tornado that caused F5 damage just south of Oklahoma City.

Warnings Can Change Types

Confirmation of a tornado might come in an update to an existing tornado warning.

For example, the tornado warning might have first been issued based on radar-indicated rotation alone.

Shortly thereafter, the National Weather Service (NWS) might receive credible information that a tornado has been sighted or has been confirmed by debris on radar. The NWS can then update the messaging in that warning to say it's confirmed.

Chris Dolce has been a senior digital meteorologist with weather.com for nearly 15 years after beginning his career with The Weather Channel in the early 2000s.