Why do they set off the tornado sirens when there is only a severe thunderstorm warning?

Question

Why do they set off the tornado sirens when there is only a severe thunderstorm warning?

Answer 1

When a Thunderstorm Warning with Tornado Watch is issued the sirens are set off for 1 min.

During a Tornado Warning the siren will continue to go off until warning is over.

Answer 2

Police, firemen, trained spotters or the I like this one.... "public" reported a funnel cloud or tornado on the ground and the National Weather Service has not issued a tornado warning or they feel the storm is not going to produce a tornado and will not issue a warning based on 1 or 2 people calling a possible funnel in.  When a member of the general public calls in a possible funnel they may be seeing something else that may resemble a tornado such as scud clouds, shelf or roll cloud, or low hanging harmless cloud. More then likely (this has happened in my area in suburbs of Chicago) that it was no funnel or tornado just an anxious person who thought they saw something.

Answer 3

That's an interesting question. Where I'm from in the Midwest, the sirens go off only for a tornado warning. Maybe they want to tell you to take cover because sometimes in a severe thunderstorm warning, a tornado can form. But glass can also shatter in winds and maybe they like you to treat it as a tornado warning to stay safe.

Answer 4

A Thunderstorm Warning means that a severe thunder has been spotted and may produce a tornado.  Many times they will sound the sirens when rotation has been spotted.  This isn't a tornado but can quickly become one.

Answer 5

When there is a severe thunderstorm, tornadoes could form, and they are just warning people to take precautions in case there is a tornado.

Answer 6

The local rules can differ as to when to sound the sirens.  Some communities will sound the sirens only if a NWS Tornado warning has been issued for their community.  Other will sound them if a tornado or severe thunderstorm watch is in effect and a reliable spotter or other trained energency official spots and reports what they believe was a developing funnel cloud heading toward their community.  The sounding of the community emergency sirens is usually up to the responsibility of the local community officials and not by the NWS.

Please note that not all communities have the same rules as to when to sound of the sirens.  Civil Emergency Community Sirens are sounded to alert residents of some type of an emergency in effect for that local area.  It is up to the state, county, and/or local community to set up the community rules as to when they should sound off the sirens.  In some places, sirens are sounded off for dam failure, nuclear power plant mishap, toxic chemical refinery mishap, or anything that needs the immediate attention of the local community.

These days, the most likely community wide emergency are weather related.  When a sirens is heard, quickly glance around to see if you can spot the hazard that may be developing near where you are.  If nothing is spotted, tune in to your media and information source to find out what is going on.  

If you are traveling away from home and you hear a civil emergency siren going off, do not assume it is for a tornado.  You may be looking for a basement to take shelter when the sirens may be for you to get to higher ground as the storm may have caused a nearby dam to fail.   Always try to get the details if you can not indentify the emergency.

Answer 7

There might have been some weak rotation in the storm which could produce a tornado but it's not necessary to issue a tornado warning when it's only weak rotation. They just might have wanted the public to be aware of a tornado forming because it might have been capable of producing a tornado or there might have been a tornado warning that you weren't aware of.