Wind damage is typically directed into one direction and can create its vast damage along a relatively straight path. 4) In the storm reported areas, at least three reports, separated by 39.8 miles (64 km) or more, should include wind gusts greater than 64 knots, or 74 mph (119 kph). Who typically sees derechos and how common are they? Derechos occur mainly across the central and eastern U.S., where many locations are affected one to two times per year on average. The downburst cluster family, in descending order of the size of affected area, consists of derechos, downburst cluster, downburst, microburst. In fact, a derecho’s path of damage is at least 240 miles long. For example, in the cool season, If the high-pressure ridge is located off the east coast and the trough of low pressure is located over Central Plains then a serial derecho could possibly occur over the Southeast U.S. The stage roof structure collapsing toward spectators at the Indiana State Fair. Questions? Some derechos, however, occur during cooler weather and are most likely to form in the region stretching from Texas across the Southeast. For instance, a swath of storms should consistently produce wind reports as the system moves to the east or southeast. Regardless, derechos tend to produce widespread damage, unlike tornadoes, which produce isolated damage. Derechos are often referred to as inland hurricanes due to the hurricanelike conditions, in terms of ferocious wind and torrential rain, which are spawned by this weather phenomenon. Also consider that outflow from strong thunderstorms may send the storm’s strongest winds before the thunderstorm – with its heavy rain, lightning or hail – actually hits you. Derechos in the United States typically occur along two axes. Derechos in North America form predominantly from April to August, peaking in frequency from May into July. In Berlin and surrounding areas, 8 people were killed and 39 were injured, mainly from falling trees. Bottom line: Derechos are very powerful, destructive wind storms that typically occur during the warm late spring and summer months. JetStream, Comments? Areas most likely to experience derechos across the United States. What is a derecho? Also, derechos tend to occur in families or groups. All the weather we experience at ground level is governed by the weather pattern in the atmosphere, and derechos are no different. With this is mind, derechos are serious storms. Simon Toogood in Tasmania – an island south of the Australian mainland – told us that stormy weather and shelf clouds like these are common in his part of the world, too. However, there have been stronger tornadoes associated with derechos in some instances. Derechos start with thunderstorms whereby frontal zones outrun cold fronts. This is precisely what occurred on April 4-5, 2011 when a serial derecho produced over 1,200 high wind reports (blue dots on image right). As the performance progressed, officials did decide to cancel the show and were putting together an evacuation plan for those in the audience. The strong-to-violent winds typically move ahead of the main system, as the outflow from the storms becomes more concentrated. In the mid-summer, derechos occur further north in north western Ontario as well as Manitoba. One axis extends along the "Corn Belt" from the upper Mississippi Valley into the Ohio Valley. In this post, we’ll look at how a derecho is formed, and where they occur. US Dept of Commerce Monster sunspot AR2786 swings into better view. Where derechos are likely to occur NOAA SPC website/Dennis Cain NOAA defines a derecho as, “(pronounced similar to "deh-REY-cho" in English, or pronounced phonetically as "") a …