Tornadoes have sporadically impacted the U.S. state of Massachusetts since at least the 17th century, when multiple suspected and confirmed tornadoes caused damage to the then-British colony. Massachusetts is far removed from the traditional Tornado Alley, as its far northeastern position in the Contiguous United States usually causes the necessary collision of cool, dry air from the Southwest, and warm, humid, air from the Gulf of Mexico to be far to the state's southwest. However, tornadoes, including strong to violent (E/F4) tornadoes still occasionally occur in Massachusetts, at a rate of 1.4 tornadoes per 10,000 square miles per year. The first tornado recorded in Massachusetts was likely one of two probable tornadoes recorded in 1671, in Cape Ann and Rehoboth. The first confirmed tornado was in 1680, in Lexington, which caused possibly the first recorded tornado fatality in history. By far the most significant tornado in Massachusetts history is the Worcester tornado of 1953, which caused 94 of the 105 recorded fatalities in Massachusetts tornado history.
Climatology Generally, tornadoes in Massachusetts occur in the summer months of June and July, which allows for the greater heat and moisture required for tornadoes to push into the state. This aligns with the general trend of tornado frequency moving north as the year progresses, due to the absence of sufficient heat and moisture in the early months of the year.
While the Atlantic Ocean provides ample heat and moisture in the summer, very rarely does the state see required elevated mixed layer that helps build instability in the atmosphere. Since the elevated mixed layer originates over the southeast, a very precise atmospheric setup needs to be in place to transport the stable air to Massachusetts untouched. This setup involves a prominent upper-level ridge over the southeastern United States, as well as a rather intense upper-level trough in eastern Canada, which is quite rare due to the decreased strength of the jet stream in the summer. A 2004 paper found that only 34 times since 1970 an elevated mixed layer associated with a significant severe weather had occurred in the Northeastern United States.
Since tornadoes in Massachusetts almost exclusively form in the summer, wind shear is also less common and less intense. The jet stream also drives the formation of low pressure areas, which cause the southerly winds that create shear with more westerly upper-level winds. Since the jet stream is weaker in the summer, generally both less intense low-level and upper-level winds are observed.
Intense to violent tornadoes are generally confined to Worcester County and the extreme western Berkshires, on the border with New York. Tornadoes in the Berkshires are likely influenced by complex terrain of area. After leaving the Catskills in New York, supercells are aided by locally enhanced moisture and southerly winds in the Hudson River Valley due to valley channeling. In addition, the complex terrain of the Berkshires can cause the mesocyclones of supercells to stretch, increasing rotational velocity and potentially leading to tornadogenesis. The violent Great Barrington tornado, which began just east of the New York border, west of Great Barrington, was aided by both of these factors.
History
Pre–1700 Date F/EF# Deaths Injuries Hardest-hit communityJuly 5, 1643?10Essex CountyThis storm was possibly the first recorded tornado, although Thomas Grazulis believes it was likely a downburst or severe straight-line wind gust. Massachusetts governor John Winthrop observed "a sudden gust that whipped up dust, lifted up his meeting house, and killed a nearby observer with a fallen tree."1671F100Cape AnnA "whirlwind" crossed a neck on Cape Ann, likely near Gloucester, Massachusetts. Although it was only about 40 feet wide, it "bore away whatever it met in the way, both small and great trees," A large rock in the harbor was also turned over.August, 1671F100RehobethFirst Rehobeth Tornado – This probable tornado, the first of three to impact Rehobeth, was documented by Rev. William Adams of Ipswich in his diary. Mentioned on October 16th, 1671, the tornado is said to have been 330 feet wide and to have possibly tracked for 15 miles, about a mile and a half south of the town, in the vicinity of modern-day Seekonk. Adams reported the tornado "[tore] up by the roots, or [broke] the bodies of almost all trees within its compass saving only some small and low ones."July 8, 1680 F110LexingtonSee article on this tornado – The first confirmed, observed tornado in United States history caused damage to a barn and snapped many large trees. Rev. Increase Mather recorded two detailed eyewitness accounts in An Essay for the Recording of Illustrious Providences. John Robbins, a servant, was killed due to bruises and broken bones sustained from flying debris. Robbins is possibly the first recorded tornado fatality.
1700 – 1799