Average number of annual tornadoes by state (1953-2004) (National Climatic Data Center)

I reviewed the Tornado History Project database and found that from August 21, 1951 to July 23, 2008 - there were 152 recorded tornadoes in Massachusetts or, on average, almost three per year. The majority of the tornadoes to strike the state were of the weaker variety, that is, F0 and F1s on the Fujita Scale. However, around 30 F2s, several F3 and three F4 tornadoes occurred during the period of record.

The National Climatic Data Center indicates about one strong to violent (F2-F5) tornado hits Massachusetts each year.

Average number of strong-violent (F2-F5) tornadoes per year per 10,000 square miles by state (National Climatic Data Center)

The two most notable F4 tornadoes to hit Massachusetts - prior to yesterday - occurred on June 9, 1953 and May 29, 1995. The 1953 storm, which touched down around Worcester, killed 94 people. The 1995 storm, which carved a path through Berkshire county, killed three people.

Tornadoes within a 25 mile radius of Springfield since 1950. Green symbols are unclassified. Orange shade is F4, yellow shade F3, tan F2, white F1 and F0. (Tornadopaths.org)

It is not yet known how intense the tornado that hit Springfield yesterday was - nor the several others that touched down in the region. A team from the National Weather Service will assess the damage today and assign an Enhanced Fujita scale rating.

More on Springfield, Massachusetts tornado:

Tornadoes in central and western Massachusetts kill at least 4 (photo and video)