Tornadoes

What is a Tornado Hazard?

According to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud." Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven't found it so simple in practice, however, to classify and define tornadoes. For example, the difference is unclear between a strong mesocyclone (parent thunderstorm circulation) on the ground, and a large, weak tornado. There is also disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes. It is well-known that a tornado may not have a visible funnel.

From the NOAA FAQ website on Tornadoes

Tornados in Rhode Island?

Tornadoes in Providence are quite rare with only 5 occurring in Providence County between 1985 and 1989. Since tornadoes are usually spawned during a severe summer storm. It is still advisable to understand the warning signs of a tornado and to seek shelter during a severe lightning and thunderstorm.

The most devastating tornado ever to occur in New England was the Worcester Tornado of July 9, 1953. The tornado hit Worcester at 5:08 p.m. Within one minute more than 90 people were dead and over 1,300 injured. Damage estimates were placed in excess of $52 million. Another damaging tornado occurred in Windsor Locks, Connecticut at about 3 p.m. on October 3, 1979. This twister lasted only about 45-60 seconds, but managed to kill 3 people, injure over 300, destroy 40 homes and cause $300 million in property damage.

The most recent killer tornado to strike New England occurred on May 29, 1995, in Great Barrington, Massachusetts. This tornado, with winds in excess of 200 mph, killed 3 people, injured 23 and caused an estimated $25 million in damage.

On average the United States experiences 100,000 thunderstorms each year and approximately 1,000 tornadoes develop from these storms. Damage from tornadoes is caused as a result of high wind velocity and wind blown debris. Over 80% of tornadoes strike between noon and midnight. "Tornado season" is marked from March through August, although tornadoes may occur at any time of the year. Normally, a tornado will stay on the ground for no more than 20 minutes. Injuries and deaths most often occur when buildings collapse. The tornadoes experienced in recent history in New England have been generated by severe summer storms.

Courtesy of NESEC (Northeast States Emergency Consortium)

Web Resources

• FEMA Storm Watch
• National Weather Service
• RI Tornadoes 1950 -1995
• Don't forget to get a NOAA Weather Alert Radio!