At least one dead after derecho blows through the Northeast

A dangerous line of storms caused damaging winds along a path of hundreds of miles on April 29, causing widespread damage.

Transcript

00:00A deadly deratio moved through parts of the Ohio Valley and through the Northeast.

00:05This is an event that did lead to one life lost in the Pittsburgh area after power lines came down.

00:11There was an electrocution associated with this.

00:14Again, deratios are when we have hundreds of miles.

00:17We've had hundreds of miles, over 400 miles of wind damage,

00:21and a continuous path here across parts of the Ohio Valley and through much of the Northeast.

00:26It's just a nasty event here from Tuesday.

00:29So what is a deratio?

00:30Here we're looking at widespread, long-lived windstorms associated with fast-moving showers and thunderstorms,

00:36straight-line wind events.

00:37Occasional tornado threats can spin up within these,

00:39but it's predominantly a straight-line wind event of at least 58 miles per hour.

00:43Some instances with far greater winds, we'll talk about that in a few seconds,

00:47are going at least 400 miles without much of any breaks in that 400-plus mile path.

00:52This exceeded that.

00:53Width was at least 60 miles from one side to the other.

00:55Pittsburgh, by the way, had its third-greatest wind gust on record at Pittsburgh International Airport.

01:0171-mile-per-hour gust in the middle of this deratio in the Pittsburgh area here,

01:06and that was kind of near the midpoint.

01:08If we look at deratio occurrence, there are areas that average more than one deratio a year.

01:13You get four every three years on average here in areas around Joplin and into Bartlesville, Oklahoma,

01:18and east of there into Fayetteville, Arkansas.

01:21Some areas get one every year here, about one every year in these areas in the deeper purple.

01:28And then you get about one every two years where some of this expanded east into central Pennsylvania,

01:32and then one every four years, about 25 percent of years, have a deratio here in, say, the eastern Carolina.

01:39So this is a very rare event.

01:41And we're getting into deratio season, April, May, June, and July.