A rare widespread, damaging wind storm took place on Saturday, and it was quite likely Colorado’s first-ever derecho on record.
Colorado weather is a lot of things, but one thing it’s not: boring.
What appeared to be a fairly typical Colorado afternoon of wind-producing storms Saturday morphed into possibly the most widespread wind-specific thunderstorm event in the state’s recorded history.
Russ Schumacher, Colorado’s state climatologist, made that contention Sunday while pointing to a number of data points.
“In the storm data record from 1955-2018, the most severe wind reports on a single day in Colorado is 30, on May 22, 2006. (Saturday), there were 91.The most significant wind gusts (75 mph or greater) on a single day was 7, on a couple different occasions. (Saturday) there were 17,” Schumacher said. “I think it’s fair to say we’ve never had such a widespread damaging thunderstorm wind event in Colorado, at least since reliable records have been collected.”
One thing that appears abundantly clear: Saturday’s story was likely Colorado’s first-ever significant derecho on record.
A derecho is a wide and long-lived line of damage-producing severe thunderstorms, but they’re far more common in the eastern half of the country. While individual thunderstorms produce damage all the time in Colorado, it’s rare to get a long, nearly uniform line of damaging storms like the one the Denver area saw Saturday afternoon.
Colorado-based meteorologist Dakota Smith captured a nearly 12-hour satellite and lightning loop showing the powerful line of storms as it raced through Utah, Colorado and eventually moved into Nebraska and the Dakotas on Saturday night.
According to Elizabeth Leitman, a meteorologist with the SPC, Saturday’s line of storms more than fit the SPC’s official definition of a derecho. Leitman said the storms produced damage for “at least” 750 miles (three times the official criteria for a derecho), producing wind gusts that fit the criteria along the way as well.
I put together some quick info on Saturday’s derecho event. Only two other derechoes in the Great Basin are well noted in literature. I’ve included storm reports for those events, as well as a derecho frequency map for comparison. Pretty remarkable event! #derecho #wxtwitter
In her tweet, Leitman also contends that far northwestern Colorado was clipped by a derecho in 1994, but that’s believed to be the only other derecho to impact the state in recorded history, or at least since reliable weather records began. Saturday’s derecho was unique in the fact that it covered a big geographical chunk of the state, unlike the 1994 event that merely clipped a small sliver of Colorado.
And, of course, getting any sort of a derecho is rare in the much drier western third of the United States. Dr. Sam Ng, a professor of meteorology at Metro State University, showed the climatology of derechos, and specifically how they tend to concentrate in the Midwest.
Indeed they are. Here’s a Derecho Climatology from SPC. Derechos for the High Plains are rare. #cowx https://twitter.com/bianchiweather/status/1269489291119308801 …Chris Bianchi@BianchiWeather
Today’s Colorado windstorm was likely a derecho- a very rare, prolonged/widespread/strong wind event for the Front Range. https://twitter.com/DocWX/status/1269488789203808258 …