Photographed late last week near Simla, Colo. (Kelly DeLay)
On June 4, a lone supercell thunderstorm developed southeast of Denver and moved south near the city of Simla, Colo. Chasers say the storm produced as many as four tornadoes, and although the National Weather Service in Boulder surveyed tornado damage up to EF-1, they have not been able to confirm exactly how many tornadoes the monster supercell produced.
But this amazing shot from storm chaser and photographer Kelly DeLay explains a little bit about the storm that had weather geeks in awe last week: at one point, the supercell had two tornadoes under it, simultaneously.
Many different photos and videos of this storm have been shared, and it does seem that one of the tornadoes was rotating anticyclonically — or clockwise — which is a pretty rare occurrence. Just like mid-latitude cyclones and hurricanes, tornadoes in the Northern Hemisphere tend to rotate counter-clockwise, along with their parent thunderstorms, because of the rotation of the Earth and the Coriolis effect.
But every once in a while, a tornado will buck that rule, according to leading tornado researcher and director of the Center for Severe Weather Research Josh Wurman. “Anticyclonic tornadoes can form if a supercell contains an anticyclonic mesocyclone,” said Wurman. “Or, a pair of tornadoes, one cyclonic, one anticyclonic, can form. Both of these are rare.”
DeLay says the storm was an amazing thing to witness and photograph. “The tornado on the left was anticyclonic, the cone tornado on the right was cyclonic, and it was persistent,” he said. “This was a beautiful storm, very large and powerful obviously.”
The photo’s perspective is what makes it so stunning. While it’s thrilling to see tornadoes up-close, you can learn a lot about a storm when you take a step back. “When I chase storms, I like to stay back for the most part so I can see structure,” said DeLay. “I am interested in the whole picture not just if it produces a tornado.”
“Because of the road network, I chose to come up from the back side of the storm, which put me into the hail, BUT what a view!” DeLay said. Indeed.
Wurman says that while true twin tornadoes are possible (like the twin tornado storm in Pilger, Neb., nearly one year ago) he doesn’t suspect this storm is an example of it.
“Many supercell thunderstorms contain ‘multiple vortex mesocyclones,'” Wurman said. “In some cases, these MVMC’s spawn two, or even several, tornado-intensity vortices that extend to the ground. If these are intense, and if visibility is good, each of these appears to be an individual tornado, and they often rotate around each other as they revolve around the parent MVMC.”
Instead, the Simla storm appears to have produced one tornado associated with the main rotating updraft, and then another that was more like a landspout. “Often, tornadic supercells contain intense wind shear boundaries far away from the main tornado,” said Wurman. “Sometimes intense vortices form along these boundaries, resulting in landspout-type tornadoes. The photograph of the Simla storm is a beautiful example of this.”
You can follow Kelly DeLay on Twitter and Instagram @kellydelay.
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