Following a four-county inspection of Tuesday afternoon's storm damage, including the Great Barrington and Sheffield areas, investigators from the National Weather Service in Albany, N.Y., reported no evidence of a tornado.
Based on radar images and a tip from a trained spotter in the small town of Copake, N.Y., just across the state line from Mount Washington in southwest Berkshire County, the government forecasters issued a tornado warning at 4:57 p.m. Tuesday for eastern Columbia County and south Berkshire. A second warning went out at 5:30, aimed at Litchfield, County, Conn.
According to warning coordinating meteorologist Steve DiRienzo, the team that went out just after dawn on Wednesday found evidence of high winds at 50 to 60 mph. Large hailstones damaged trees and cars, the investigators stated, and there was straight-line wind damage to trees as well as some minor lowland flooding caused by three and a half inches of rain in the Copake area.
"The guys found nothing consistent with tornado damage," DiRienzo said Wednesday afternoon. "They also talked to fire department and police officers, as well as utility crews and no one saw evidence of a tornado."
But a microburst, akin to a water-filled balloon dropping out of the sky, caused a partial shutdown of Route 71 between Egremont and Austerlitz, N.Y., as three separate storms deluged the area late Tuesday.
DiRienzo, who made the decision to issue the tornado warnings, explained that "we warn based on what we see on radar. Also, a spotter claimed he saw a tornado, but video we've seen showed no touchdown from the wall cloud."
"It was a powerful storm," DiRienzo acknowledged. "But somebody [the spotter] got a little excited, nervous and scared so we wanted to get the warning out."
"You go with the information you have at the time," he pointed out. "Hindsight is always 20-20. But our mission is to protect life and property."
The storm-survey team checked six towns in Columbia and Dutchess Counties, N.Y., as well as Berkshire and Litchfield. Their stops included Copake, Boston Corners, N.Y., Falls Village and Canaan, Conn., and finally Great Barrington and Sheffield.
Berkshire County was included in a severe thunderstorm watch issued Wednesday afternoon, but DiRienzo noted conditions were less volatile because cloud cover had held temperatures down to the low 70s. Pre-dawn storms on Wednesday dropped more than an inch of rain in Pittsfield and Lanesborough, and more than two inches in North Adams and Clarksburg, according to weather observers. A flood warning for the Hoosic River in Williamstown is in effect until Thursday morning, with minor flooding predicted.
According to Raymond O'Keefe, meteorologist in charge of the Albany office, about 70 percent of tornado warnings in the Northeast turn out to be false alarms, since it's more difficult to interpret radar data for the weaker storms typical of the region, compared to massive twisters like the one that devastated Moore, Okla., on Monday.
"I have no reason to believe a warning shouldn't have gone out based on the radar and the information from the trained spotter," said O'Keefe as he reviewed the data that led to the Copake storm alert.
"We run our people through simulation and training," he noted. "We take great pride in knowing the best science available and using the meteorology we've been trained in. We make the decision to issue warnings objectively, based on radar and reports from the field."
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