Usually when we spot a rainbow, we think of clearing skies, improving weather and the quiet, peaceful beauty of a departing storm.
Some people even caught the tornado and rainbow intersecting. It may be the most visually striking example of a tornado-rainbow combination since the famous Mulvane, Kans., tornado of June 12, 2004.
Friday’s classic severe weather setup produced at least half a dozen tornadoes, in addition to numerous instances of large to giant hail and damaging winds. There were no reports of injuries associated with the tornadoes, which posed against ominous dark skies for an audience of storm chasers peppered about the surrounding landscape.
The funnels all dropped out of one lone rotating supercell thunderstorm, which tracked a path from Childress, Tex., 15 miles from the southwest corner of Oklahoma to near Vernon, Tex., about 60 miles east-southeast. A trio of storms fired along a dryline, or the boundary between encroaching dry desert air to the west and mild, moisture-rich air streaming in from the Gulf of Mexico to the east.
The tornadic storm was anchored to a center of low pressure and its associated triple point — the apex where several air masses meet, which served as an extra source of storm rotation.
While tornadoes often form in hotter conditions, the temperature this time was in the low 70s. The air was humid enough near the ground to support development of storms, which exploded upward into frigid air aloft. Surrounding dry air in the borderline “cold core” setup eroded much of the cloud cover outside storms, allowing for blue skies and sunshine visible from beneath the potent cells.
Somehow I overlooked this photo when doing a quick edit last night. This is my new all-time favorite photo I have taken. Still trying to process the awesomeness that happened yesterday.#txwx #tornado #rainbow #ExtremeWeather#severeweather @StormHour #Canon #canonphotography pic.twitter.com/tbhcKayRdI— Greg McLaughlin (@GregMc_wx) April 24, 2021
Ryan Shepard, a storm chaser and tour guide for Silver Lining Tours, was operating the group’s Close Encounters Tour, which began April 21 out of Oklahoma City. Guests paid $3,500 to chase until May 1 under the auspices of experienced professionals. He captured a mesmerizing photo of a tornado posing with a rainbow that quickly went viral.
“I was guiding for our first storm chase tour of the season,” he wrote in a Twitter message. “We had a mix of seasoned guests and a few new ones. Some of them got to see their first tornadoes on this day.”
The relatively dry air also made for comparatively high cloud bases, meaning the funnels were taller and more readily visible. For travelers on Texas Highway 70 driving in from the west, the tornado was the first thing they encountered — before any rain, hail or even thunder. Tornadoes form on the backside of supercell thunderstorms.
It was the perfect environment for a double rainbow. Some photographers even lined up the shot such that the rainbow actually went through the tornado. Tornadoes are made of water condensate and entrain raindrops, and rain was being swept south behind the funnel in a region called the “rear flank downdraft.”
In the photo below, one can see the edge of the rear flank downdraft, which was carrying ping-pong-ball-size hail, as it wraps counterclockwise around the rotation. Its southern extent is the milky-white curtain of rain and hail. Also note how the rainbow appears to end there since it’s the cutoff of where precipitation is falling:
In other photos, a dark area can also be seen between the primary and secondary arcs. That’s known as Alexander’s Dark Band and results from the direction where sunlight is scattered. Given how sunlight travels through the raindrops and is split into component colors and bounced along ray paths, sunlight returning from raindrops in that band can’t reach the observer. That’s why there’s a local minimum in brightness.
As the tornado began to weaken, it didn’t just vanish or dissipate — instead, it roped out in spectacular fashion. Its bottom could no longer keep up with the top of the funnel, meaning the storm was dragging it northeastward. That stretched it and tilted it more horizontally; that stretching yielded a narrower, but perhaps more quickly-rotating funnel, commensurate with the conservation of angular momentum. It’s the same premise at play when a spinning ice skater pulls their arms inward and spins faster.
Meanwhile, more tornadoes could be in the offing. Another day with isolated to widely scattered supercell thunderstorms is forecast on Tuesday across parts of western Oklahoma and the Texas Panhandle and Hill Country. Flooding may become problematic as storms continue through the Southern Plains and Midwest on Wednesday.
More spectacular sky views:
I think this is my favorite still image from the Lockett/Vernon tornadoes on Friday. A 2 shot pano to get all of the rainbow with the tornado almost perfectly centered. @weatherchannel @StephanieAbrams @JimCantore @JenCarfagno #tornado #rainbow #txwx pic.twitter.com/O7pX1wE9y1— Charles Peek (@CharlesPeekWX) April 25, 2021