Chugwater Tornadic Supercell
Chugwater WY, 20 Jun 10
SHORT: Observed tornado from second of two supercells E of Chugwater.
LONG: Since Scotts Bluff National Monument was just a few blocks from our motel doorstep, we had time for some late morning through midday hiking, as well as photographing wildflowers and other interesting scenery near the top, before grabbing a quick lunch and heading west to our target area of southeast WY. See, for us, the so-called “storm chase” vacation isn’t just about storms, but about appreciation of as much of the Great plains’ offerings of beauty and wonder, large and small, as possible — storms being the major component, but not the entire experience. And so it was that we strolled atop the bluff o’ tuff, pondering the view up this way from the Oregon Trail’s wagon trains rolling up the North Platte valley below, while also occasionally looking at surface maps and satellite images on our I-Phones, and considering the effect the stable air represented by this stratified overcast would have on the day’s convective potential.
Thin breaks and occasional peeks at the sun indicated some destabilization was occurring, in an area of nicely backed surface winds from there westward, and automated mesoanalyses of CAPE and CINH fields bore that hunch out. As we descended from the hill, as if on cue, the first towers began to erupt over the Laramie Range, where the clouds had been eroded over the highest terrain in the area, allowing maximum heating. We couldn’t see them through the stratus, of course, and I had doubts about how far E convection could make it off the mountains before getting into grunge and weakening There was no doubt we needed to follow Horace Greeley’s old advice and “go west”. As we did so, two storms started to rotate:
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1. A cell in the Wheatland/Dwyer area, headed NE toward Jay Em but also toward some decidedly stable air, and
2. A storm moving somewhat more slowly and seemingly anchored along the foothills near Chugwater.
We went through Torrington along the way, then SW, catching a brief view of the distant and uninspiring base of the northern storm, before moving SW toward an area of obvious darkness above and beyond the intervening stratus deck. By the time we got to a good vantage W of Yoder and S of veteran WY, the southern storm, which had been a supercell, already was losing definition in its base and soon would turn into a strung-out, most likely elevated plume of convection.
Fortunately, the strong heating continued off the W edge of the stratus deck and the E edge of the mountains, firing additional convection still farther SW. With the boundary layer continuing to get more unstable in that direction, we backed through Yoder and S again past Hawk Springs. Then we then headed up the beautiful bluffs E of Chugwater along one of my favorite drives in the region (WY-313), only to greet an already well-developed and obviously surface-based storm by the time we arose on the high plateau E of I-25. The storm was calving off left splits, one of which can be seen beyond an abandoned farm structure in this shot looking WNW. Turning our attention to the WSW, the large, robust right mover quickly cut a clear slot and formed a broad, rotating, bowl-shaped lowering
behind it (and above the letter “s” ending my name in this wide-angle shot). This was only a few minutes after we had arrived at our location, and then, at 1624 MDT (2224 Z)…
T-TIME!
You see, in most years, a tornado is such a rare and amazing event to witness for any storm observer. This year, I had experienced lousy luck with tornado photography in what has been a banner season for some others. In most cases (e.g., Bowdle SD, Faith SD, Campo CO), I wasn’t available to chase on the fantastic day in question. On one (10 May, OK), I (along with some other very talented chasers) got on the one storm that refused to produce anything more than a brief spinup while observable. On another (16 Jun, SD), the storm blocked the only safe road access to it with flooding and hooks filled with both precip and precip-wrapped tornadoes, while also going nuts on the other side.
After all that tornadic frustration, then, it surely felt good to see one that was not low-contrast, rain-wrapped and/or too brief to photograph, even if it was a small and otherwise not very newsworthy hose. The tornado slowly roamed wide-open land and, to our knowledge, hit no structures of consequence — just the way we like it. As seen from about 3-4 miles to its E, the tornado manifest initially as a tapering cone (zoom), with two episodes of visible ground contact. The first is shown in this zoom (see wide angle structure view), followed by a few minutes where neither condensation nor dust was evident under the base of the funnel (wide angle structure view), followed by a few minutes where full condensation planted again.
That vacillation was described by some observers as separating two tornadoes that occurred from the same vortex (by definition, a tornado must have ground contact), while others deemed it as one tornado with a weak interlude. What is a tornado? The ground was soaked out there, minimizing dust, although it did lose full-condensation again before lofting some combination of spray and dust (super wide, with storm structure). The tornado started to wrap deeply back into its occluding mesocyclone, then roped out.
Tornado-wise, that was all the storm could do. We felt fortunate to get there just in time! We also had to bail east, off the high plateau, because hailstones of 2 inches and larger in diameter started falling around us with discomforting splats and thuds right as I was shooting the last rope-out photo. We got out from under the vault with no hail impacts, then headed S and E in a very difficult effort to find a good W-NW view of the weakening supercell that wasn’t overly obstructed by terrain. Some others we know weren’t so lucky with hail. At that vantage, we encountered the Tempest bunch with Chuck, Chad Cowan, and Bill Reid, here shown calling for lodging from behind two giant hail craters patched with duct tape. Not far to our W, as the tornado began to narrow, that part of the vault immediately downshear from the low-level mesocyclone unceremoniously heaved forth gorilla hailstones up to 4 inches in diameter. It’s a good thing nobody was hurt by that hail (a vastly under-appreciated injury hazard in storm observing)!
The supercell moved over progressively more stable low-level air while attempting to backbuild, and eventually just died. That left us with no storm and some daylight, which we used for traveling to our motel in Sidney. On the way down toward I-90, we stopped to photograph an abandoned farm with soft stratocu and baby-blue sky in the background. We then hopped on the Interstate for a very unusual (for late June!) plunge through a late-afternoon regime of cool fog and mist, in the stratified air mass E of where the supercell had been.
Comments
6 Comments on Chugwater Tornadic Supercell
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Dann Cianca on
Tue, 10th Aug 2010 8:53 pm
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tornado on
Wed, 11th Aug 2010 10:55 am
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Dann Cianca on
Sat, 14th Aug 2010 11:12 am
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tornado on
Sat, 14th Aug 2010 12:32 pm
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2010 Chase Season Dénouement : Storms Observed this Year on
Sat, 14th Aug 2010 2:24 pm
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Dann Cianca on
Sun, 15th Aug 2010 9:44 am
Great photos, Roger and a great account as well. This was a very frustrating day for myself and Tony Laubach, whom I was chasing with. Though we were on WY313 not ten miles east of Chugwater during the tornado’s life cycle, we did not witness it. I still am not sure how this happened. We did, however, see the hail and saw some poor folks whose front windshield was obliterated.
Dann — I’m stumped as to how y’all didn’t see that tornado! We were 11.5 E of Chugwater on 313, and the terrain W of us was flat to very gently rolling for several miles (it did drop off the plateau just to our E). If you were only a couple miles to our W at tornado time, you would have been closer to the tornado, presumably with a really fine view not far from where Tempest and Brian Morganti were. That is, until the hail hit, which beat the crap out of their vehicles before the tornado was over. What time were you ~10 E of Chugwater on 313? Maybe I can correspond that with the photo (tornado) times and see what your angle of view would have been.
Hi Roger,
Well, going back through my pictures and footage, it appears that when the tornado touched down, we were actually just leaving Chugwater. I have video of us passing by the white greenhouse located at 3ESE Chugwater at 2227Z. In thoery, the tornado should have been readily visible not far to our south at this point. Considering that the road jutted south just outside of Chugwater, I’m not sure how we didn’t see it. However, the storm reports (three from this particular tornado) have the tornado in three distinctly different places. Maybe you could point me to your best estimate, with respect to Chugwater, where the tornado actually touched down. Thank you.
Dann,
The tornado times I’ve got in the camera are 2224-2229Z. I was 11.5 E Chugwater on 313, estimating the tornado to be ~5 miles WSW, which would put it about 6 E of Chugwater. We thought that surely it was visible from I-25, given the lack of thick precip around its W side; indeed, given the nature of the silhouetting as seen from the E, it might have been a beautiful white cone as seen from the W or NW.
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Hi Roger,
Thank you for discussing this with me and helping me figure it out! It appears, then, that in all likelihood, the tornado was obscured by precip as at the time we were in the rain and had the hail core between us and the tornado. The tornado reports didn’t show up until we were much further down the road. Thanks again.