JLab Tornado Preparedness - Tornado Facts
(Reminder: Jefferson Lab will conduct a Tornado Preparedness Drill on Tuesday, March 18 from 9:45 a.m. to 9:50 a.m.)
Tornadoes are probably not high on the list of weather concerns for most Virginia residents, but they are more frequent than you might expect.
Last year, Virginia experienced just two tornadoes, but in 2006 there were 16 across the state that caused nearly a half-million dollars in damage. One of those 2006 tornadoes struck Jamestown on Jan. 11, causing minor damage at the Jamestown Beach Campground and Foxfield subdivision.
On average, July is the most active month for tornadoes in Virginia. The month's hot, humid days are often accompanied by a late afternoon or evening thunderstorm. The hot temperatures and humidity of the late afternoon fuel the thunderstorm's growth.
Hurricanes or the remnants of strong hurricanes also can spawn tornadoes. The daily and annual records for tornadoes were set in 2004, when 87 tornadoes struck the Commonwealth. The remnants of Hurricane Ivan resulted in 40 tornadoes on Sept. 7, setting Virginia.s record for the most tornadoes in a single day.
Virginia's tidewater counties also experience a fair amount of tornado activity due to Chesapeake Bay and the coast. Waterspouts are common and occasionally will come onshore and do some damage. Once the waterspout comes onshore, it is considered a tornado. In 2000, 16 waterspouts were reported and three moved onto land as a tornado. Another reason for tornadoes in this area is that often during the warm months there is a bay breeze or sea breeze front (bay or sea cooled air on one side of the front and land heated air on the other). When a large rotating thunderstorm moves over a boundary/front such as this, there is an increased chance that conditions will be right for the development of a tornado.
If a tornado were approaching, would you know the warning signs?
According to the Virginia Department of Emergency Management, if you see any of these signs you should take immediate action:
- 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.
Of course the best course of action is to stay tuned to your local radio or TV for weather reports, or listen to a NOAA weather radio for more detailed information when weather conditions are favorable for the formation of tornadoes.
Remember, the safest place during a tornado is typically a building's basement away from any windows. If there is no basement, go to a windowless interior room such as a closet, bathroom or interior hall on the lowest level of the building.