What is a derecho? The U.S. Midwest faces worrisome storm threat
A powerful line of thunderstorms is expected to sweep across a large portion of the U.S. Midwest Monday, bringing strong winds, baseball-sized hail, and a risk of tornadoes. On top of that, the storm complex could result in a derecho, a rare and dangerous phenomenon.
The U.S. National Weather Service's Storm Prediction Center (SPC) issued a clear warning for Monday: Severe thunderstorms are expected this afternoon and evening in an area stretching from South Dakota to southern Minnesota and northern Iowa.
These thunderstorms could generate damaging gusts reaching 120 km/h to 145 km/h. Hail up to the size of a tennis ball could also fall in some areas. The warning also mentions the risk of tornadoes.
SEE ALSO: Decoding the deadly derecho: How fierce it was in Central Canada
What is a derecho? It's a highly organized line of thunderstorms, often moving at a high speed and causing wind damage that can exceed 400 kilometres.
This type of system is often able to maintain its intensity well passed sunset by tracking along a stationary front that separates two opposing air masses.
The SPC has placed a portion of the U.S. Midwest under a 45 per cent probability of damaging winds by Tuesday morning. More than 1.2 million people live in the region, where the risk of damaging thunderstorms is rated as moderate.
Seen in Canada
Although derechos occur more frequently in the central U.S. states, this type of phenomenon is not unknown in Canada. The most recent confirmed case was in May 2022, when a derecho system stretched more than 1,500 kilometres--from Windsor, Ont., to Quebec City, Que., resulting in 12 fatalities and hundreds of thousands without power.
DON'T MISS: From nuisance to nightmare: Huge hail is an extreme danger
There is some speculation that on Sunday, July 27, a line of severe thunderstorms over northwestern Ontario, might be classified as a derecho. These events, like tornado ratings, only get the name derecho after a damage investigation by Environment and Climate Change Canada (ECCC) and the Western University-based, Northern Tornadoes Project (NTP).
There appears to be no threat to Canadians with Monday’s U.S. severe storm setup. However, these events may be possible as summer heat persists.
This article was translated to English from MétéoMédia, The Weather Network’s Quebec-based sister station.