(WWLP) – Investigators from the National Weather Service determined that a tornado touched down in the Middlesex County town of Concord during the early morning hours Monday.
While some tornadoes (such as the one that struck Springfield and several other western Massachusetts communities in 2011) are plainly seen, overnight storms are much more difficult to judge. As a result, meteorologists have to survey the damage in the daylight to determine whether it was indeed a tornado, or a microburst.
The NWS says that it is the pattern of the damage, not the amount of damage, which indicates whether a tornado has taken place.
Here is how they can tell:
- In a tornado, debris is strewn every which way- uprooted trees often cross each other.
- In a microburst, downed trees and other debris usually always lands in the same direction- creating the appearance that trees were “flattened.”
Large, uprooted trees are generally seen as the most reliable indicator of whether a storm produced a tornado or microburst, because smaller trees or branches may simply fall due to the weakness of the plant itself, rather than in the direction of the wind.
Meteorologists also look for possible twisting damage to trees, which would be indicative of a tornado.
Even during storms in which the existence of a tornado is not in question, NWS meteorologists conduct surveys to determine the intensity of the twister. The Enhanced Fujita Scale is used to classify tornadoes based on their maximum wind speed.
- EF-0: Wind speeds 65-85 MPH
- EF-1: Wind speeds 86-110 MPH
- EF-2: Wind speeds 111-135 MPH
- EF-3: Wind speeds 136-165 MPH
- EF-4: Wind speeds 166 to 200 MPH
- EF-5: Wind speeds greater than 200 MPH