Derecho winds slamming the Midwest last week

Last week, very strong winds moved through the central portions of the country, knocking out power and causing some widespread damage.

One of the cities that was hardest hit was Houston. A line of intense thunderstorms ripped through the region May 24 with wind gusts estimated to be as high as 100 miles per hour. The high winds resulted in windows being blown out of buildings, including skyscrapers in the middle of the city. Trees, power lines and many electrical transmission towers were taken down by the strong storm. Nearly 750,000 people were left without power. According to the Storm Prediction Center, this region of severe thunderstorms produced very strong winds across an approximate 400-mile path from Nebraska to Illinois.

These strong winds from last week’s storm were classified as a “derecho.” Known as a widespread and long-lived wind storm, derechos are associated with a fast-moving group of heavy thunderstorms. According to the Storm Prediction Center, to be classified as a derecho, winds are at least 58 miles per hour with occasional gusts topping 75 miles per hour, and the damage often occurs in one direction along a straight path of at least 250 miles.

Most of these big storms occur in the spring and summer months. However, there have been reports of these massive storms as late as October. In 2010, severe storms that developed from the Gulf Coast to the Great Lakes likely included derechos Oct. 23-28, the latest in recorded weather history.

The destruction associated with a derecho is similar to a tornado. The event usually produces hurricane-force winds, heavy rainfall and flash flooding. Officially, a tornado is a rotating column of air that comes in contact with the ground.

Derechos are rare events, but in 2020, there have been seven occurrences in the U.S. Since 2010, there have been a total of 46 reported derechos. For this year, counting the latest storm, there have been three reported derechos in the U.S.

These massive storms have also been reported in other parts of the world. For example, in 2023, a derecho hit the far northern part of the Alpine mountains in Germany and continued into Slovakia. There was another one last year in the northern portion of Italy on July 19. On Dec. 16-17, a line of thunderstorms moved through Buenos Aires in South America that resulted in extensive damage. One of the strongest derechos outside the U.S. also occurred in South America. On Jan. 16-18, 2005, there was a huge derecho that downed over 540 million trees in the Amazon Rainforest in Brazil.

Due to the mountainous terrain, there have not been any derechos reported around North Idaho. However, many will never forget a system of historic proportions slamming into the northwestern portion of the country Nov. 16, 2015. Very strong winds led to numerous power outages, downed trees and power lines and damaged buildings. Over one million people were left without power across the Northwest.

On that November day, winds were gusting to 60 miles per hour at Cliff’s station on Player Drive. The highest wind speed reported in Idaho was in Bonner County at Colburn with a whopping 101-mile-per-hour gust. The strongest wind gust in eastern Washington last November occurred at the Mission Ridge Ski Area in Chelan County with an incredible gust of 137 miles per hour.

In terms of our local weather, our May precipitation total as of Sunday is 1.86 inches at Cliff’s station in Coeur d’Alene. Our average rainfall for this month is 2.37 inches. There is the possibility of some moisture this week that could bring our monthly May total to nearly 2 inches, but it does look like our final total will end up a little below average.

Most of our moisture this month has come from two storms. On May 5 and 6, that system produced 0.77 inches of rain in Coeur d’Alene. On May 22, another storm dumped 0.91 inches of moisture, which led to some area flooding. One other system May 18-19 dropped only 0.16 inches in Coeur d’Alene.

Despite the slightly drier than normal month, our annual rainfall moisture total is close to normal with 11.54 inches. However, we are currently behind last year’s figure of 12.30 inches.

At the Spokane International Airport, the moisture total for May is much lower as only 0.79 inches of rain has fallen. The normal precipitation for this month is around 1.25 inches. Since Jan. 1, the airport has received 6.44 inches of rain and melted snow, compared to the normal to date of about 7.75 inches.

Looking further ahead weatherwise, there is a chance of some moisture next week, but it doesn’t appear this system is going to be very strong. The longer-range computer models are suggesting some very warm weather early next month that could have high temperatures challenging the 90-degree mark.

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Contact Randy Mann at randy@longrangeweather.com.