SWAW, Day 4: Tornado Safety Information

It's Severe Weather Awareness Week in MN and WI, which means its time to start going over what everything is again and what precautions to take when severe weather strikes. The Storm Prediction Center has a Slight Risk of Severe Storms Friday just south and east of the STC area, so now is as good as time as any to relearn what we do in summertime, like how we have to relearn the winter warnings (and how to drive) in the winter. Remember, throughout the summer we'll cover it the best we can on Facebook, Twitter, and now Blogger. Today's topic, brought to you by the National Weather Service, is Tornado Safety -- I've also included what a watch and warning is, along with the procedure for today's drills, siren information, and a few other local facts thanks to Paul Douglas.

Tornado Safety Information


Atmospheric conditions are favorable for the development of severe thunderstorms capable of producing tornadoes.


A severe thunderstorm has developed and has either produced a tornado or radar has indicated intense low level rotation in the presence of atmospheric conditions conducive to tornado development.

Before the Tornado... Tornado watches highlight the area where tornadoes are most likely to develop. Continue with your normal activities, but keep informed of the latest weather information and be ready to get to shelter in case tornadoes develop quickly.

In the Home... Go to the basement if possible. Get under a table, work bench, or some other sturdy furniture to avoid falling debris. A stairwell is also a good place to hide during a tornado.

If You Cannot Get to a Basement... Go to a small interior room on the lowest floor. Closets, bathrooms, and interior halls afford the best protection in most cases, or try to hide under a bed. Get under something sturdy or cover yourself with blankets. Stay away from windows.

In an Apartment, School or Office Building... Move to the inner-most room on the lowest level or to a pre-designated shelter area. Stay away from windows. If in a hallway, crouch down and protect your head from flying debris. Avoid areas with glass and large roof expansions.

In a Mobile Home, Car, Truck or Other Vehicle... Abandon these as quickly as possible. Seek a sturdy shelter or permanent structure. Remember that many deaths occur when people try to drive away in a vehicle, but get caught in the deadly winds. Avoid bridges since they act as wind tunnels.

Last year, Minnesota saw 43 tornadoes, a typical number since the early 90s. The strongest were three tornadoes rated EF-3, one in Hugo on May 25, another near Park Rapids on June 6, and one near Willmar on July 11. There was one fatality, as a 2 year old boy was killed in Hugo on May 25. There were also 24 injuries across the state. The closest tornado to the St. Cloud area was in Sherburne County.

The earliest verified tornado in Minnesota occurred on March 18, 1968, north of Truman, and the latest in any year on November 16, 1931, east of Maple Plain.

Historically and statistically, June is the month of greatest frequency with July not far behind. May has the third greatest frequency, followed closely by August. Nearly 3/4 of all tornadoes in Minnesota have occurred during the three months of May (16%), June (34%), and July (26%)

Wisconsin had 38 tornadoes last year, but only one reached the category of EF-3, and that was a bizarre tornado on January 7 near Powers Lake. There was one other tornado on January 7 near Kenosha. These were only the 2nd and 3rd tornadoes ever to strike Wisconsin in January. There were no tornado-related deaths in Wisconsin last year, but 21 people were injured.

Tornado Watch/Warning Drills

The National Weather Service, Wisconsin Emergency Management, the Minnesota Division of Homeland Security and Emergency Management, and other state, county and local agencies have come together to host Severe Weather Awareness Week activities. On Thursday, April 23rd, simulated tornado watches and warnings will be issued to test the statewide warning and communications systems. The schedule for April 23rd is as follows:

(all times CDT)

9:00 AM: The National Weather Service will issue a simulated tornado watch for Minnesota (except the northwest portion of the state).

1:00 PM: The National Weather Service will issue a simulated tornado watch for Wisconsin.

1:40 PM: The National Weather Service will issue a simulated tornado warning for 9 counties of western Wisconsin (Barron, Chippewa, Dunn, Eau Claire, Pepin, Pierce, Polk, Rusk and St Croix). Note that most cities and counties will activate outdoor warning siren systems.

1:45 PM: The National Weather Service will issue a simulated tornado warning for Minnesota counties (except those in the northwestern part of the state). Note that most cities and counties will activate outdoor warning siren systems.

2:00 PM: The National Weather Service will issue an "End of Test" message using the Severe Weather Statement product. It should be stated that outdoor warning sirens will not be sounded again for this all clear, nor will there be any warning tone on NOAA Weather Radio.

6:55 PM: Another simulated tornado warning will be issued for participating counties in Minnesota. Those counties are: Anoka, Benton, Big Stone, Brown, Carver, Cass, Chippewa, Chisago, Cottonwood, Crow Wing, Dakota, Douglas, Freeborn, Goodhue, Hennepin, Isanti, Jackson, Kandiyohi, Lac Qui Parle, Lake, Le Sueur, Lyon, Martin, McLeod, Meeker, Mille Lacs, Morrison, Mower, Murray, Nicollet, Nobles, Olmsted, Pine, Pipestone, Pope, Ramsey, Redwood, Renville, Rice, Rock, Scott, Sherburne, Stearns, Steele, Stevens, Swift, Todd, Traverse, Wabasha, Waseca, Washington, Watonwan, Winona and Wright.

A graphic of the counties participating in the evening drill is available at http://www.severeweather.state.mn.us/Documents/Participating_Counties_Drill_Map_2009.pdf

The 6:55 PM warning will be issued by five of the National Weather Service offices that serve Minnesota. It will be issued as a test of family preparedness in the home and for second shift workers.

Siren Activation Information

Counties and cities own the sirens, and therefore decide how and when to activate them. The National Weather Service does not sound them.

There are many different policies regarding siren activation that are used by the various cities and counties. 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. Some will activate sirens across the entire county for tornado warnings and severe thunderstorms that have winds of at least 70 or 75 mph. 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.

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.

There is no such thing as an "all-clear" for storms.

Please check with your local public safety officials for details on when warning sirens are sounded in your community.