Severe Weather Awareness Week: Alert Systems 17 Apr 12

Severe Weather Awareness Week in Minnesota
Monday, April 16: Alert Systems
Chris Weldon, Scott County Emergency Management Director

Outdoor Warning Sirens

We all need to understand that these types of sirens are meant to be heard outdoors for people that are away from a TV or radio. If you can hear them indoors it’s an added bonus for you. A better option for receiving alerts when indoors is a NOAA weather radio. These can be programmed to receive watches and warnings for specific areas and are especially helpful for receiving notifications at night.

There are many different policies regarding siren activation that are used by the cities and counties in Minnesota. Some will activate sirens across the entire county for tornado warnings only. Others will activate sirens countywide for tornado warnings and all severe thunderstorm warnings while others will activate sirens only for portions of counties. Local officials may also sound the sirens anytime they believe severe weather is a threat, even if there is no warning from the National Weather Service.

Scott County will typically activate outdoor warning sirens if a tornado warning is issued. Initially the sirens will go off only for the cities that are included in that warning. If it looks like public safety requires it the decision to activate for other cities may follow. Sirens can also be activated upon the request of the police or fire chief or if a law enforcement officer observes potentially severe weather. We may also activate sirens if a trained weather spotter reports high winds or observes any type of rotation in the storm clouds that might lead to a tornado.

If you hear these sirens you should take cover and turn on a radio or TV to find out what is happening. The sirens or weather radio should be considered your first steps in deciding what you will do next.

Sirens normally sound for about three minutes, and then go silent. It is very rare to keep the sirens sounding for the entire warning, since that would cause the backup battery to run out, which would be critical in the event that power goes out. Furthermore, the siren motor will fail much more quickly if the siren sounds continuously. Some jurisdictions may repeat siren activation every few minutes.

Also please remember, there is no such thing as an “all-clear” siren. If you hear additional sirens, stayed tuned to TV and or radio and don’t venture outside until you know the threat has passed.

Other alerting systems

The National Weather Service and many local media outlets offer electronic alerting services that provide email, RSS feeds or text messages to cell phones, computers or other devices, either directly or via services such as Facebook, Twitter or others. These messages are available by voluntary subscription and can provide local information on weather, including watches and warnings. Receiving a text message could be a quick and easy way to stay on top of threatening weather if your activities take you outside and other media sources are not readily available. Check with your service provider to see if charges are incurred when receiving these types of alerts.