A Derecho is a line of intense, widespread, and fast-moving windstorms and sometimes thunderstorms that moves across a great distance and is characterized by damaging winds.
Knowing that, it’s easy to see why Saturday’s wind and rain event is being classified as an official derecho but seeing the dynamics come together to create conditions favorable for derecho formation in the intermountain west is exceedingly rare. In Meteorology, in order to have a verified derecho there needs to be a storm path of at least 240 miles long and wind gusts reported of 58 mph or better along that path.
There are only two documented derechos that have impacted the western United States. One happened in May of 1994 and one in June of 2002. So, to say this is a rare, exceedingly rare event is completely valid.
Here’s What Happened
Around 9 AM on Saturday the first wind and hail report came from this line of storms in southeast Utah. Close to 12 hour later, the last wind report was measured in southwest North Dakota. This derecho unofficially covered a distance of close to 900 miles!
This line of storms moved from Utah to North Dakota travelling at an average speed of 60 mph but at times, this storm was moving at 100-120 mph!
What makes this exceedingly rare is that this derecho crossed over the Continental Divide in Colorado which consists of multiple 13,000-foot mountains and typically tears apart storms due to its dramatic topography but this derecho was strong enough to overcome that.
As this derecho moved into the Front Range it brought heavy rain and a decent amount of small hail. This will go down as the first and only severe weather event that Denver has seen in 2020.
The Winds That Ripped Apart Our Trees
The winds were the biggest component of this derecho. Here’s a list of some of the peak wind gusts we saw in Colorado and along the Front Range:
Winter Park Resort: 110 mph
Copper Mountain: 90 mph
Denver International: 78 mph
Commerce City: 73 mph
Broomfield: 71 mph
Morrison: 70 mph
Monument: 61 mph
Dillon: 60 mph
Loveland: 58 mph
Suffice to say, this is the reason that there was so much tree damage and even some structural damage across the region.
You just lived through some pretty substantial Colorado weather history. Remember this one because it’s likely we won’t see something similar to that for quite some time, if ever.
~ Rain or Shine
I’m Andy Stein