The storm that rolled across the U.S. yesterday, killing at least two, leaving thousands without power and scrubbing more than 1,000 flights, was a weak version of a rare windstorm known as a derecho.
The storm, spawned by a larger cold front that stretched from Texas to the Northeast, “was certainly a low-end derecho,” said Stephen Corfidi, a meteorologist at the U.S. Storm Prediction Center in Norman, Oklahoma.
A derecho is defined as having gusts of at least 58 miles (93 kilometer) per hour and leaving a swath of damage for a minimum of 240 miles.
“As far as it being on par with what occurred on June 29, no,” Corfidi said, referring to a more powerful storm that killed at least 24 and left 4.3 million people without power from New Jersey to North Carolina. “It wasn’t right up there with the earlier event.”
New York Assistant Attorney General Richard Schwartz was killed by the storm, according to a statement from Attorney General Eric T. Schneiderman. Schwartz died after lightning knocked bricks and a scaffolding off a church in the Cobble Hill neighborhood of Brooklyn, the New York Post reported.
A woman in Genesee, Pennsylvania, was killed when a tree fell on her, according to AccuWeather Inc.
About 386,000 customers in five states lost power, the majority in New York and Pennsylvania. The storm also spawned a possible tornado in Elmira, New York, in Chemung County, and caused so much damage there that Governor Andrew M. Cuomo declared a state of emergency for the region.
As of 12:30 p.m. there were still 43,000 customers in New York without power, Cuomo’s office said in a statement.
In addition to the deaths and power outages, 1,012 flights were canceled in the U.S. yesterday. LaGuardia Airport in New York was hardest hit with 180 departures scrubbed, said FlightAware, a tracking company based in Houston.
Corfidi said the derecho didn’t have more power in New York City because thunderstorms earlier in the day upset atmospheric conditions the system needed to gain strength.
It also tended to follow two main nodes of thunderstorms, one of which passed to the north of the city while the other diverged south toward Trenton, New Jersey, he said.
Severe thunderstorms and tornadoes have been the most damaging U.S. natural disasters in the first six months of 2012, according to the Insurance Information Institute in New York. The storms have caused at least $8.8 billion in insured losses.