What Is A “Derecho”?

The internet is a big part of almost everyone’s lives nowadays and that includes social networking sites like Facebook and Twitter. The inspiration for this post comes from my personal Facebook page, where my mother has made it a habit to post anything somewhat weather related to my timeline. On July 27th, she posted a link of a storm system that had moved through much of eastern United States the day before. I read the article and was intrigued by the “Derecho” that had hit major cities, like New York, just one day before so I decided to do a little research.

According to the SPC, a Derecho is storm system that is at least 240 miles long with wind gusts of 58 mph or greater along much of the system. The winds are caused by downbursts which is a concentrated area of strong wind produced by a convective downdraft that could be 4-6 miles wide and last for several minutes. For a Derecho to form, there needs to be what the SPC likes to call a “downburst cluster” that could be 50-60 miles wide and last for tens of minutes. The destruction that comes from these can be like that or a tornado, but for the most part the damage is in one direction along a relatively straight swath. The storm system can also produce hail, heavy rains, flash flooding, and even tornadoes.

On July 26th, 2012, a Derecho hit the eastern United States stretching from Connecticut down into northern Texas. With the storm, there were more than 400 wind reports and 30 hail reports, and 9 tornado reports. According to Taylor Berman of the website “Gawker,” almost 300,000 homes lost power in New York State, Pennsylvania, and Ohio, and at least 840 flights were grounded in the path of the storm.

-Stephanie Waldref