Mothership Madness - Apex Chase August 6th, 2019 Part III - Escape
Mar 8, 2020 | By: Storm Chase Tour Of The Great Plains
Part III - Escaping Alien Invasion
At approximately 8:20pm CST, our chase began to wind down, or at least so we thought. The sunset's last flicker of light had illuminated the highest tops of our mothership storm and blue hour began to creep in, bringing lower light and much more visible lightning. Our storm, beginning to descend further away from us to the southeast, but still close enough to create dramatic compositions and observations, still intrigued us enough to continue making observations.
Sunset turns to blue hour storm chasing
We wrapped up our position near Iona, South Dakota and tried to find unobscured compositions on highway 47 heading south into increasing hillsides and tougher terrain to observe the storm. We found positioning on a hilltop dirt road a few miles before Gregory, SD and witnessed incredible lightning as it illuminated the mesocyclone and mammatus clouds connecting the anvil above our storm, at an incredible 67,000 feet above. To our west, the clear sunset sky began to fade as the first stars began to emerge directly overhead.
It was at this point that we noted a surprising new cell directly to our north with increasing lightning. This new initiation did not exist an hour earlier so it was suprising to see such a strong signal on radar emerge so quickly right on the heals of our mothership.
As we drew our attention back to our original mothership, the last light begin to drift into total darkness, and we wrapped up an intensely memorable blue hour shoot witnessing the round disc mothership leave our visibility for the last time. The lightning was near constant as it generated intense flashes from its now 67,000 foot top down to the low base. We observed rotations several times and some rather suspect lowerings and potential rain-wrapped circulation at that point but did not make enough observation to call into the NWS office to report tornadic activity at that point.
As we loaded up gear and prepared to wrap up the chase, we couldnt both help but attempt to abosorb what we saw that evening. Witnessing such a perfect mothership supercell was such an incredible moment in time. From initiation near Gettysburg, we chased this storm for nearly 5 hours and over 175 miles, nearly half that with the mothership. We jumped in the car, heads filled with impossible visions, memory cards filled to capacity with truly unique and exclusive content as we made our way to the town of Gregory, SD, hoping for some late night snacks and fuel for our long drive back to Colorado.
While reaching near Gregory, SD that the now fully evolved storm to the north had taken hold over the area directly ahead of us. By this point, all restaurant and even gas station snack options were non-existent as the town was essentially shut down for all but fuel. Not discouraged, we figured we could get snacks later on our route home. But the chasers in us couldn't help but note the storm to the north began to exhibit some very strong mesocyclone readings and intense, very very intense lightning not far from our position.
Last moments with our mothership before it faded from our view
We agreed we could spend a couple last moments documenting the storm and its increasingly violent lightning near the airport east of Gregory as we had good exit routes to the east and west to allow us to escape before the storm likely hit the area. Chasing at night brings a level of awareness and much safer planning as there are many more variables to account for. Distance to the incoming cell, road obstacles and fatigue play a very big role and our own pratice kept us well aware of conditions as the storm began its forward motion to our position.
The new cell to our north continued to intensify as it tracked closer to Burke, SD. It appeared that persistent warm advection at 850 mb was fueling the new cell while robust SR bulk wind shear helped to keep it's updraft very organized. At this time new thunderstorm activity was rapidly developing in the moist and unstable air to our south. We knew that we would have to keep an eye on these storms as they were in the direction of our escape path. We decided to end our chase and observations in Burke around 10:20pm and take our southern escape route before the tornadic activity began.
Peaking at 66kft About 2 minutes before the tornado hits Burke, SD
At 10:25pm the new supercell peaked as it passed directly over Burke, SD and produced an EF 1 tornado. The tornado began near the Burke Fire Department building -- which is located one block east of Main Street with top wind speeds measured at 110 miles per hour. The tornado touched down at 10:25 p.m. near the city’s center, before lifting up eight minutes later south of town. The path measured 3.8 miles and was about 75 yards wide. This tornado inflicted heavy damage to parts of the town as did severe front line winds also in excess of 100mph.
The tornado hits downtown Burke, SDCredit NWS Sioux Falls
Shortly after producing the tornado, the supercell became outflow dominant and sent a powerful wave of rain cooled air screaming to the south at speeds greater than 75 mph. As the outflow boundary continued south, it began to interact with ongoing thunderstorm activity across northern Nebraska. New storms began to fire along the boundary's leading edge and proceeded to merge with the existing storms into what would become an intense MCS that would last for an extraordinary 24 hours and travel 1100 miles finally dissipating in Arkansas having wreaked havoc over 6 states during its long life cycle.
As we made our last observations of the storm south of Burke, we experienced a touch of the front line winds and made one last documentation of the new cell before heading to Ainsworth, NE and to relative safety away from the now intense MCS event that would rock the midwest for the next 24 hours.
The carnage went well into the night after we ended our chase
Our chase 08-06-19
Looking back, our chase was so well planned, and we were very fortunate to have a great road network, lack of traffic and safe pullovers to observe our storm. To witness the storm for 5 hours and see such a wide variety of color, light, texture and incredible structure during the evening was something we will both cherish for a long time. Observing how storms interact with the Missouri River, terrain and feeding on the 850mb winds really gave us great insight to future parameters for South Dakota chasing and we can't wait to go back!