A small tornado was spotted Thursday in Black Forest, a reminder that Colorado may not be part of “tornado alley,” but eastern El Paso County is no stranger to small twisters.
About 4:30 p.m. Thursday, a relatively “brief and weak” tornado touched down in Black Forest, according to the National Weather Service in Pueblo. Video evidence of the storm left meteorologists rating the tornado at 0 on the Enhanced Fujita scale. The scale rates tornadoes based on wind speed and damage, weather service meteorologist Greg Heavener said.
Thursday’s EF-0 tornado was half a mile long and 15 yards wide, with a peak wind speed of 70 mph. Some EF-5 tornadoes in the Midwest have been estimated at more than 200 mph.
Little to no damage occurred Thursday, said Heavener, which is why meteorologists used video footage to rank the twister.
Eastern Colorado is especially prone to twisters, according to National Weather Service data.
“(The eastern plains) get some pretty big ones,” Heavener said.
For a tornado to develop, he explained, there needs to be enough moisture in the atmosphere to produce lower clouds, horizontally rotating air standing vertically and a thunderstorm. Colorado’s moisture comes primarily from the Pacific Ocean, he said.
The best analogy to explain how tornadoes work, said Heavener, is to think of a figure skater doing a spin. The tighter the skater brings in their arms to their body, the more conservation of angular momentum.
“If you’re able to stretch a column of vertical air, it’ll make it spin faster,” said Heavener.
The faster a tornado rotates, the deadlier it can be.
Colorado’s eastern plains are closer to a moisture source and often get the aftermath of storms that develop in the mountains and move east. Studies show that the state’s tornado season typically begins in April and trails off by the end of September.
Though Colorado is considered a moderate climate, some areas with higher moisture levels have seen their fair share of twisters, including El Paso County. Thursday’s small whirlwind marked the second recorded tornado of the year for the county, after another tornado touched down near Falcon in March.
El Paso County has had 30 recorded tornadoes since 1995, weather service data shows. Eastern counties such as Kiowa and Prowers have racked up between 40 and 60.
by Liz Henderson (2019, Aug 9 | Updated 2019, Aug 10) The Gazette