Chasing Supercells in South Dakota and Wyoming

The word "awesome" is way overused these days, but that's really the only word to describe the incredible power of severe weather, which has always fascinated me. I've seen hurricanes at the ocean, kayaked in tropical storms, seen crazy fronts and photographed tons of lightning, but never a supercell thunderstorm or a tornado. Tornadoes are (fortunately) rare, and that, coupled with the obvious danger, means that to see one I wanted some expert help. And so, back in February, I went to the National Storm Chaser Convention in Denver and learned a lot, and ended up enrolling in an online meterology class this summer. At the convention, I met Roger Hill, who organizes the whole event.  Hill runs regularly scheduled tours during tornado seaon, and also does "on call" tours when conditions look favorable for supercell thunderstorms, which create most tornadoes.

I was just getting caught up from my Ireland/England trip when I got an email from Roger last Monday, saying that conditions might be favorable for severe weather Thursday and Friday in the area of North and South Dakota. I figured with school starting soon, this was my last chance at seeing anything this year. So on Wednesday, when Roger gave the "Go", I found a plane ticket and flew to Denver.  My objectives were first, to see some states I had never been to before (I've been to about all but 10), and I hope, see a super cell. A tornado would be a bonus.

Roger picked me up at a Denver airport hotel Thursday morning, and our small group--just Roger, Cathy (a geologist from Denver) and I--hit the road. Roger decides where things look favorable based on the forecasts from the Storm Prediction Center, and a huge number of other models, observations, and satellite imagery, all accessible in real time via a mobile wireless connection in the van, overlaid with our current GPS position.  Most of all, though, Roger bases his decisions on where to go on 25 years or so of experience chasing storms, and he has an excellent track record.  The decision about where to position yourself is critical in order to be close enough to get to storms in time when they start to develop (and things change very fast).

We headed north from Denver into eastern Wyoming, where we eventually found a storm that was looking interesting on the radar. It turned out to be an anti-cyclonic supercell, unlikely to produce a tornado, but it was beautiful to watch. (Click any image for larger version).

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There was a huge amount of lightning, which unfortunately I couldn't photograph in the daylight (I'm buying one of these soon). Apparently, anti-cyclonic supercells typically don't survive very long, and this one seemed to be weakening, so we headed off looking for another one. We stopped to grab some food, and a storm we had been watching pulsed up again and we set off after it, with the light fading. 

It never got too severe, but we did get a nice lightning show:

We headed to Shadron, Nebraska for the night, to be in good position for the next day.  I had ticked two states off my list (South Dakota and Nebraska), and seen a couple supercells. More photos here.

The next morning, the SPC was issuing predictions for a good chance of severe storms around Pierre, SD, and so Roger's plan was to head to Pierre area and wait to see what developed.  On the way, the SPC completely revised its outlook, cancelling the Pierre outlook for severe storms and instead issuing two zones pretty much on opposite ends, east and west, of South Dakota.  Roger agonized about the decision, and thought that with the surface conditions, it wasn't likely that we would see a tornado if we went west, but would likely see either a tornado or nothing if we went (very far) east.  We headed west, and I did talk the group into stopping by the infamous Wall Drug store for a few minutes (another thing checked off the list).

Heading into Sturgis, where the motorcycle rally was in its final day, we watched the clouds and the radar, and saw a bunch of stuff developing nearby, but none of it ever seemed to be able to get enough momentum to really become severe. So we headed to Wyoming again where things were starting to break out, and drove through some small hail and ended up watching a beautiful show by two massive supercells:

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(Note, the white vertical area reaching the ground in the photo above isn't part of the cloud, it's hail.)

Around this time, Roger noticed that another storm had, in, fact, developed and was heading straight for Sturgis.  So we packed up the cameras and screamed back to South Dakota. We arrived just after the storm did (more photos in my earlier write up here):

We picked up the chase, heading east as fast as we could.  We eventually started catching up with the monster storm, which was still churning away, hours after it pummelled Sturgis:

You can see the rotation in the storm indicated in the horizontal bands--it's rotating counter clockwise (typical for the northern hemisphere).  We finally got out in front of it, but there were no roads to go north to get closer (the storm was moving pretty much due east at this point).

We quickly gassed up in Wall, and then headed north up a dirt road, playing catch up again:

We finally got out in front of it, but the light was fading:

It was one of the most beautiful and eerie things I've ever seen, as it moved towards us, the only sound being the rustling of the wind.  Here's a series of stills in sequence, showing the movement:

Roger already needed to replace his windshield due to previous hail damage, and so he pointed the van into the storm and we rode it out. Turn up the sound for this one, it was incredibly loud (I was very happy I had my earplugs in!):

What doesn't show up in the video is that a meso-cyclone passed just to our right. It was not a tornado, but with the lowering clouds from the updraft rotating and the intense winds, it was really scary looking. Eventually, we had enough and had to get out of there. We out ran the storm, but needed to go south, and the lack of roads meant we now had to right back through the core again, this time with the hail dangerously pounding us from the side. I climbed in the back of the van to get away from the passenger side windows in case they blew out.

Finally, with Roger's expert driving, we cleared the storm, and could stop to assess the damage.  Not only was the windshield done, but the left front turn signal had been destroyed and knocked off the van; the right front mirror signal was also knocked off, and there was a dent the size of a dinner plate in the front hood (near the raw metal):

We arrived at our motel in North Platte after 1am.  It was a long day (with dinner at a McDonalds near midnight), but well worth it; lots more photos here. We got back to Denver Sunday afternoon, and I finally had my first real meal (storm chasing is not for foodies--you're always on the go) and  full night's sleep of the trip.

So the trip most definitely met and exceeded all my expectations and objectives, and now I want to see a tornado even more. But that will have to wait for another time, most likely again under Roger Hill's excellent guidance.