WASHINGTON — It’s been two years since a powerful derecho blew through the Washington area. Tuesday’s wind storm conjured memories of the 2012 incident and its aftermath.
“This all started with the extreme wind event during the evening of June 29, 2012. Ever since then, every wind event in the area seems to be compared to that event and called a derecho, ” says Greg Carbin, Warning Coordination Meteorologist at the National Weather Service’s Storm Prediction Center in Norman, Oklahoma. According to him, the July 8 storm that raced through the Mid-Atlantic and southern New England area was a damaging wind event, but he steered clear of referring to the entire weather system as a derecho.
“Yesterday’s event was characterized by straight-line winds … We had a lot of reports of trees down. It’s always going to be some level of interpretation that’s necessary for these things.”
Carbin says that classifying the weather event as a derecho would require further analysis and verification of measured wind speeds within the storm’s path.
A derecho is loosely defined as a sprawling line of storms over 250 miles in length that produces a near-continuous swath of wind damage and wind gusts over 59 miles per hour for at least six hours.
“Did we have measured wind gusts that met severe thunderstorm criteria across that entire swath? I don’t think we’ll get those measurements to be sure. It’s always going to be some level of interpretation that’s necessary for these things.”
It was the storm’s southern fringes that lashed Washington. Locally, winds gusted between 45 and 61 mph. The storm’s fiercest winds occurred north of Washington. A 61 mph wind gust was recorded at Martin State Airport east of Baltimore. Sections of Pennsylvania and New York were harder hit. The Storm Prediction Center catalogued 314 reports of wind damage on Tuesday. Most of the reports were near the Mason-Dixon Line.
“That segment of the event certainly could meet the criteria of derecho.”
Regardless of the storm’s classification, Carbin says that all severe storms are dangerous.
“Just about every thunderstorm has deadly potential. Even though it may not be producing extreme wind speeds, every thunderstorm should be taken seriously.”