Serpentine Belts, Coal Dust and Purple Lightning

August 31, 2007 by
Filed under: Summary 

NE Wyoming

16 Jun 2007

SHORT: Minor midday car trouble in Bighorns, could have been much worse. Fixed. Outflow-dominant, sometimes photogenic storms intercepted in GCC and Wright areas. Top-5 favorite personal daytime lightning shot taken.

LONG:

Seldom have Elke and I had a more unpredictable and adventuresome nontornadic chase day, complete with enough twists, turns, minor intrigue, delights, frustrations and unexpected weirdness that I might have thought the ghost of Rod Serling was along for the ride.

Enticed by the potential for discrete supercells somewhere in northeast WY or southeast MT on the 16th, we drove up the day before from Denver, timing the trip for any low-probability frontal Cb development between Casper and Buffalo WY. Deprived of desired convective eruption, we grabbed a room and had a nice dinner in Buffalo, then headed up part of the Cloud Peak Skyway to see part of a range we hadn’t experienced before — the Bighorns. We were amazed at the profusion of wildflowers that cloudy evening, and vowed to criss-cross the range the following morning before resuming storm intercept activities.

The morning of the 16th, we had a great time driving, shooting photos, hiking, eagle-watching and fishing in the mountains. That is, until the car uncharacteristically overheated while climbing up-canyon from Tensleep. I pushed the old sedan too hard uphill, I guess, and it pushed back. Fortunately I noticed the temperature gauge climbing visibly and pulled over to let things cool down, hopefully before the thermostat could get damaged. This would, at a minimum, delay the chase day a bit once we reached the other side. Bummer.

As I passed the cooling time exploring under the hood, I noticed that my serpentine belt had a jagged, two-inch crack in the middle with light shining through. Big, big bummer. The belt was fine several days before, but since had entrained a pebble into its grooves which, in turn, caused a stress fray to work through to the flat, visible side. And I had forgotten to pack a spare belt before the trip…%$&#@^*! With the motor finally cooled, the thermostat still uncertain (turns out it was fine), and the all-everything belt splitting apart, we limped over Powder River Pass and through the mountains deeply burdened with automotive uncertainty. That inch-wide strip of fibrous rubber could shred any second, rendering the car useless on the spot. Up at 8,000 feet, it was approaching mid-afternoon on a Saturday, and we just hoped to get down to Buffalo and find a garage still open before the belt would rip itself to ribbons. I had all but written the chase day off. The next day was Sunday, which meant that with or without needing a AAA tow along the way, we could be stuck in Buffalo with no car for at least two days until minor but critical repairs could be done.

Stopping regularly to check the belt, cool the engine (just in case, though no more thermal spikes occurred) and do some fortuitous wildflower photography (why not?), we noticed anvils from Cb’s developing beyond the crest of the range, probably in the northern part of Bighorn Basin. Large scale ascent and destabilization aloft indeed was spreading over the area, and storm already were firing even back in the dry air. “Hell of a lot of good that will do us while stuck in town,” I thought.

Headed downhill toward Buffalo, I spotted stratus rolling in to Clear Creek Canyon from the east. This signaled upslope flow, as forecast. In turn, it signaled a pronounced easterly surface component on the adjacent plains, moist advection, and with the upper trough approaching, strong turning with height and increasing deep-layer shear. Normally I’m not a pessimist by nature, but I was imagining the spectacular supercell I wouldn’t see, except as great vaporous mountains of sunlit towers heaving skyward somewhere off to the distant NE, E or SE.

Somehow we not only made it into Buffalo, but found a gas station with a garage still open. The fuzzy-faced 18-22 year old mechanic on duty didn’t know if he either had the right part (he looked…he had one left) and could replace the belt (he did, in less than five minutes). There even was an auto parts store a block away where I could buy a spare. Best of all, this kid charged only five bucks more for parts and labor than I paid for the spare belt. The chase day was saved too; storms hadn’t fired yet either (except way north in northern MT, which was out of reach in any event). We couldn’t believe this good fortune. As for the old belt, I’m making fine use of it as a tree holder right now, tied to a pair of stakes in my yard. If you’re in Norman, stop by and I’ll show you that crack, which somehow never expanded.

It had been a day full of adventure, and the chase hadn’t even begun.

Before departing that morning, I had let the desk clerk at the Super 8 know we would be back after lunchtime to “check travel weather” on their hallway computer, so there we returned. An already long-lived supercell was grinding across north-central MT, just beginning to carve its amazing hail swath in a rampage of ice bombs that would last for five more hours. Another young storm, which would turn into an apparent LP (were any chasers on that?) was cranking up NW of BIL — a storm that would move across a decent road network N of town.

Anvil material from the high-based junkus in the Bighorns was spreading overhead, with reflectivities increasing and thunder audible. We still were N of the stationary front, so I decided to head E toward GCC and hold out for later development or evolution of something coherent as the Bighorns convection hit the Plains moist layer. Along the way, we took note of a robust young storm with an overshoot NE of BIL and visible about 75 miles NNE of us. If nothing else blew up by the time we got to GCC, we could turn N toward Broadus and let it amble across the road void toward us. Alas, the promising young storm choked and died almost as fast as it went up. As some of the high-based garbage moved off the mountains, it developed a shallow but rotating wall cloud, which went away fast but which I took as a good omen.

My oh my, had the sky ever changed (looking W) by the time we got to GCC and found a viewing vantage on the W side of town! The high based crap had evolved into a line of intensifying storms with a beautiful, tiered-shelf appearance (looking NW as it approached), and apparently some embedded mesocirculations that prompted a tornado warning or two. We moved several miles E of town, intending to take some parting shots of the outflow-dominant but photogenic mess (looking NNW and looking WSW) before evacuating S. This outflow later would contribute to the development of additional storms on the N side of the Black Hills, including the surprisingly tornadic squall-line storm along I-90.

The outflow hit, and before we could reach our south exit out of GCC, we were reduced to zero visibility in…jet-black coal dust! The outflow launched a dense streamer of powdered fossil fuel out of a pit N of the road, and we had the lousy timing of being engulfed in it! It was amazing nobody wrecked along that interstate. For a hundred yards or so, we knew what it must look like to a bug stuck inside a laser-jet printer cartridge. To add to the list of needed car maintenance, I would have to change an air filter clogged with frickin’ coal dust. Such a scenario wasn’t what I had in mind at the start of this — or any — chase day!

South out of GCC, we targeted a storm that was already TOR-warned along I-25 in southern Johnson County, moving in the general direction of Wright. I had forgotten that the terrain is almost continually higher W of WY-59, and it was most frustrating to drive 37 miles in 30 minutes for only fleeting, distant, truncated views like this one to the SW. By the time we got to Wright, three things were apparent:

1. Rotating bases would appear (as in the lowered area to the far right here, and to the near right in this shot) but would get undercut fast by all the nearby outflow,
2. The whole messy convective package was going to haul E quickly across the Thunder Basin National Grassland toward the western Black Hills, and
3. We were getting hungry and thinking about those delicious fajitas at the Fountain Inn’s Mexican restaurant.

We stopped briefly to watch the oncoming storms at a Park-n-Ride pull-off near Clareton, at WY-450 and WY-116. “Wait a cotton-pickin’ minute here…what the hell’s a Park-n-Ride doing way out in this remote, windswept corner of the northern Great Plains?”

Turns out that the coal miners commute there from Wright, Upton or Newcastle, then buses pick them up to take them to their work areas around Black Thunder (largest coal mine in the USA).

As the bases began moving overhead, occasional filaments of lightning crawled through the foregoing midlevel cloud deck with a peculiar and beautiful purplish hue, sometimes capped off by a CG in some random location in the NW, W or SW. This wasn’t getting any safer, considering I was one of the tallest objects for miles around, even while crouching low. After one last click of the shutter, in wishful effort to capture one of those pastel colored flashes, it would be time to skedaddle. That last try turned out to be one of my all-time favorites: a ghostly, lavender-toned ribbon coursing back and forth, alternating outside and just inside the bottom of the clouds, soon followed by an unseen CG off to the right (N).

I was tickled to snag one of these in-cloud strokes, but would have remembered them fondly even if I hadn’t. As I hope the image conveys, the sky scene as a whole was uniquely Great Plains in its stark, textured beauty, and set a fine table for the electrical discharges that would be dished up.

Oh yeah, food…we wanted to get to Newcastle before that restaurant closed, so we high-tailed it E, gust front nipping at our rear bumper and overtaking us at a stoplight in town. Dinner was very good, and the long, strange day finally would end with contentedly full stomachs and lots of moments upon which to reflect.

[If you’re interested, a small set of images from our evening and morning in the mountains is located in our digital trip galleries.]

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