In other words, derecho's are fast moving bands of thunderstorms in the Midwest that can create hurricane force winds. On June 29th, a derecho came through town, clocked at 83 mph. The storm was so fast moving that it left little warning or preparation time. We had several projects set up and we had several projects go down because of that storm. While the toll was rough for a tent company in terms of loss, over a hundred thousand people lost power due to the storm, some for over a week."According to the National Weather Service, a derecho is a widespread, long-lived, straight-line windstorm that is associated with a fast-moving band of severe thunderstorms. Generally, derechos are convection-induced and take on a bow echo form of squall line, forming in an area of wind divergence in the upper levels of the troposphere, within a region of low-level warm air advection and rich low-level moisture. They travel quickly in the direction of movement of their associated storms, similar to an outflow boundary (gust front), except that the wind is sustained and increases in strength behind the front, generally exceeding hurricane-force. A warm-weather phenomenon, derechos occur mostly in summer, especially during June and July in the Northern Hemisphere, within areas of moderately strong instability and moderately strong vertical wind shear. They may occur at any time of the year and occur as frequently at night as during the daylight hours."
We have not seen storm related damage like that since Hurricane Ike blew through the Midwest before it finally fizzled out. All told, a couple of dozen tents were lost due to the winds. More amazing to us were the tents that didn't fall down. There was no rhyme or reason as to why they were left standing. A structure engineered to with stand 80 mph winds got yanked 15' into the air and tossed about 75' through and past a chain link fence, but a 20x20 frame tent with no engineering or wind load design was o.k. in an open field. It's mind boggling.
In the end, no one was injured by our tents or structures and that's the most important thing to consider. It was an awesome reminder of just how powerful mother nature can be. Some times there is nothing that you can do but sit back and pick up the pieces when its all over.
What derecho damage looks like in person (photo by NBC4i.com):
What a derecho looks like on the radar (photo from the National Weather Service):
