- Strong, persistent rotation in the base of a cloud.
- Whirling dust or debris on the ground under a cloud base – tornadoes sometimes have no visible funnel.
- Hail or heavy rain followed by dead calm or a fast, intense wind shift. Many tornadoes, especially in Virginia, are wrapped in heavy precipitation and can't be seen.
- Loud, continuous roar or rumble, which doesn't fade in a few seconds like thunder.
- If it's night, look for small, bright, blue-green to white flashes at ground level (as opposed to silvery lightning up in the clouds). These lights are power lines being snapped by very strong wind, maybe a tornado.
- Persistent lowering of the cloud base.
Tornado Watches and Warnings
It is important that businesses know the difference between a tornado watch and a tornado warning, and pay attention to weather announcements during severe thunderstorms.
- A tornado watch means that conditions are favorable for a tornado and that tornadoes are possible.
- A tornado warning means that a tornado has been sighted or has been indicated by National Weather Service Doppler radar and might be headed your way. When a warning is issued, take cover immediately.
- Stay tuned to your local radio or TV for weather reports
- Listen to a NOAA weather radio for more detailed information when weather conditions are favorable for the formation of tornadoes. More information on NOAA weather radios can be found on this website under Partnerships – NOAA Weather Radios.
- Tornadoes could develop in your area.
- Stay tuned to your local radio, TV or NOAA weather radio for further information and possible warnings.
- Be prepared to take cover if necessary.
- A tornado has been sighted or has been indicated by NWS Doppler radar.
- Warnings are given to individual counties, areas or cities and include the tornado’s location, direction and speed.
- If you are in or near its path, seek shelter immediately.
- Shelter immediately in the nearest substantial building. Go to the building's basement. If there is no basement, move to a small, windowless interior room such as a closet, bathroom or interior hall on the lowest level of the building. Be sure to use the stairs to reach the lowest level, not an elevator. Protect your body from flying debris with a heavy blanket or pillows.
- If you are in an open building (shopping mall, gymnasium or civic center, etc), try to get into the restroom or an interior hallway. If there is no time to go anywhere else, seek shelter right where you are. Try to get up against something that will support or deflect falling debris. Protect your head by covering it with your arms.
- Vehicles: Get out of your vehicle and try to find shelter inside a sturdy building. A culvert or ditch can provide shelter if a substantial building is not nearby — lie down flat and cover your head with your hands. Do not take shelter under a highway overpass or bridge, because debris could get blown under them or the structures themselves could be destroyed.
- Outdoors: Try to find shelter immediately in the nearest substantial building. If no buildings are close, lie down flat in a ditch or depression and cover your head with your hands.
- Mobile homes: Do not stay in mobile homes. You should leave immediately and seek shelter inside a nearby sturdy building or lie down in a ditch away from your home, covering your head with your hands. Mobile homes are extremely unsafe during tornadoes.
Go to http://www.vaemergency.com for more information.