Severe Weather Awareness Week

Severe Weather Awareness Week
 

Radar depiction Remer/Hill City, MN tornado August 29, 2013 Figure on the left is reflectivity and on the right  is storm relative velocity.

  Are You Ready? Use this week to get informed on how to be ready, then set and go!

  Thunderstorm season is just around the corner and it is up to all of us to be aware and be prepared for what
  mother nature throws at us. 

  Thunderstorms bring lightning, heavy rain, hail, damaging winds and tornadoes. These hazards can happen any
  time, anywhere, so it is up to us to know before we go.

Learn more about Severe Weather Awareness Week in Minnesota and Wisconsin:

Minnesota Severe Weather Awareness Week

Wisconsin Severe Weather Awareness Week

The Drill

The highlight of the week will be the tornado drill on Thursday, April 20th when the National Weather Service offices in Minnesota and Wisconsin issue mock tornado watches and tornado warnings. The watch will be issued at 1:00 pm and the warnings will be issued at 1:45 pm. An evening mock tornado warning will be issued at 6:45 pm. Use these drills to practice what you would do if it were a real tornado. 

• What to do in a tornado.

NWS Severe Weather Products

 Hazardous Weather Outlook (HWO)

• The Hazardous Weather Outlook includes any potential weather hazard out to seven (7) days. It is used for planning purposes and will include a short description of what the weather threat is, when it is expected, and whether storm spotter activation will be needed. The HWO is issued daily around 5:00 AM, and updated during the day as needed. It is also broadcast on NOAA Weather Radio.

Severe Thunderstorm Watch

• A Severe Thunderstorm Watch is issued by the Storm Prediction Center (SPC) when there is a potential for severe thunderstorms to form or move into the area. A severe thunderstorm consists of wind gusts of 58 mph or higher, or 1" diameter size hail or larger. Severe Thunderstorms occasionally do produce tornadoes with little advance warning. A Watch is typically in effect for about 6 hours and covers a region of a state.

Flash Flood Watch

• A Flash Flood Watch is issued when the potential for flash flooding exists. Usually these are issued when abundant, heavy rainfall is expected from thunderstorms, especially if the ground is already near saturation. Flash Flood Watches are sometimes issued if there is a possibility of a dam failure as well.

Tornado Watch

• A Tornado Watch is issued by the Storm Prediction Center (SPC) when there is potential for severe thunderstorms that can produce tornadoes. Thunderstorms may be more severe and the atmosphere is favorable for rotation within thunderstorms and tornado development. A Watch is typically in effect for about 6 hours and covers a region of a state.

Severe Thunderstorm Warning (SVR)

• A Severe Thunderstorm Warning is issued when a thunderstorm is or is expected to produce wind gusts of 58 mph or higher, or 1" diameter size hail or larger. In this case, either severe weather has been reported or the thunderstorm looks severe based on Doppler Radar. The warning is typically in effect for 30 to 60 minutes.

Flash Flood Warning (FFW)

• A Flash Flood Warning is issued when a rapid rise in small creeks and streams is expected. Flash Flooding or mudslides are expected or occuring. The warning is typically in effect for 2 to 3 hours and covers a county.

Tornado Warning (TOR)

• A Tornado Warning is issued when a severe thunderstorm is or is expected to produce a tornado. In this case, either a tornado has been spotted or rotation is being detected within the thunderstorm on Doppler Radar. The warning is typically in effect for 30 to 60 minutes.




 
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Severe Thunderstorms

A thunderstorm is defined as severe if it produces damaging wind gusts (58 mph or higher), large hail (one inch or larger in diameter), a tornado, or a combination of these elements. Of course thunderstorms also produce deadly lightning and heavy rains. Most thunderstorms do not become severe, but for the smaller percentage that do - Severe Thunderstorm Warnings are issued.

Severe thunderstorms can occur at any time of the year, day or night. The peak season for thunderstorms is from April through September, and during the afternoon or evening hours.

The most common type of severe weather is damaging thunderstorm wind, also known as "straight line wind". Strong thunderstorm wind gusts can reach hurricane force and in extreme cases - 100+ mph. Wind damage can be extensive and affect entire counties instead of narrow tracks like tornadoes. Objects like branches, trees, barns, outbuildings, high-profile vehicles, and power lines/poles can be toppled or destroyed, but as wind gusts increase you can have damage to roofs, windows, or homes. 

Large hail is also common and can produce tremendous property damage. Usually large hail does not become life threatening unless people are outdoors without shelter. Hail is considered severe when it reaches the size of a quarter or larger.

Have a good source of weather information. When a severe thunderstorm moves into your area, or a warning is issued for your county, take action to protect yourself and property:

• • Move to a sturdy building.
  • Stay away from windows.
  • If boating or fishing, move to shore.

Flash Floods

For a full link to Flood Safety, click here.

Flash flooding, one of the leading thunderstorm killers, is a rapid rise in small creeks or streams, usually from excessive thunderstorm rains. Flash flooding can also occur with ice jams on rivers or if a dam fails. 

Respect the force of flowing water. Many automobiles become bouyant in as little as 2 feet of water, and you can lose control of your vehicle in as little as 6 inches. Even pickup trucks or SUVs may begin to float in relatively shallow water given the size of the tire. Most flash flood related deaths occur from people driving into high water. This is especially dangerous at night when people may not see the flooding and simply drive into it.

When flash flooding is observed, or a warning is issued for your county, take action to protect yourself and property:

• Move to high ground. Avoid flash flood prone areas.
• Never drive into flood waters.
• Obey all road closure or high water signs - find an alternative route if needed.
• Be especially cautious at night when it is more difficult to spot flash flooding.

 Tornadoes

A tornado is a violently rotating column of air in contact with the ground. The peak tornado months are May and June (July is 3rd), but tornadoes can occur any time of year if conditions are right. Peak tornado time is 3:00 to 9:00 PM, but they can occur day or night, and may be hard to spot or wrapped in rain at times.

Have a good source of weather information. Consider NOAA Weather Radio. If a tornado or funnel cloud is spotted, or a warning is issued for your county, take action to protect yourself.

At home...

• Move to a sturdy building. Shelters are more safe than mobile homes.
• Stay away from windows. Do not try to open or close windows.
• Stay away from outside doors and garages.
• Move to a basement and get under something sturdy.
• If you have no basement, move to the lowest level and get in an interior room, like a bathroom or closet.
• Put as many walls between you and the storm as possible.

At work...

• Move to a basement or interior hallway on the lowest level.
• Leave large span rooms.

At school...

• Leave classrooms that have windows or that are on the exterior of the building.
• Leave large span rooms, like gymnasium or auditoriums.
• Seek shelter in interior rooms and get under desks or sturdy objects.
• Be careful in hallways that may act as wind tunnels and funnel debris.
• Move students off buses and back into the school.
• Do not let students board buses during a Tornado Warning.

When traveling...

• Do not try and outrun a tornado.
• If the tornado is some distance away, drive away from it.
• If the tornado is relatively close, leave your vehicle for a sturdy building.
• If no shelter is available, seek refuge in a ditch or culvert. Crouch down and protect your head.

If outdoors...

• Find a shelter if possible.
• If boating or fishing, move to shore.
• If no shelter is available, seek refuge in a low spot. Crouch down and protect your head.