Squall Line Way Up North
St. John ND
10 Jun 12
SHORT: Blew off chasing in trees in MN or driving from ND-KS in one shot, intending to hang out in ND ’til the pattern returned favorable parameters to Dakotas. While en route to Int’l Peace Garden, intercepted photogenic, low-topped squall line and attendant arcus cloud over very green fields near St. John ND.
LONG:
The cold front from the previous day’s action was slated to shift into more forested land of central and northern Minnesota, within which we didn’t wish to chase. Strong to severe storms also were possible farther south, along and ahead of the front, in mode viewing-friendly areas of Iowa, NW Missouri and Kansas, but under weaker deep-layer shear.
Laundry beckoned, and so did a few days of R&R in the heretofore superficially explored state of North Dakota before the next substantial atmospheric perturbation brought severe potential to the northern Great Plains. After finishing the wash and brunch in Grafton, we charted a net WNW course on the township-range zigzag of eastern and northern North Dakota, aiming to grab a couple bucketfuls of rich, black soil from the old Lake Agassiz bed for my vegetable garden back home (check), visit Icelandic State Park (uncheck), see the Pembina Gorge (check), visit the International Peace Garden (check), and spend a night or two in the so-called Turtle Mountains (check).
Somewhat retracing the route we took the evening before, we encountered a fantastic layer of asperatus (a.k.a. “warm-advection clouds”) between Grafton and Cavalier. That was followed immediately by a rather featureless, messy band of elevated thunderstorms that timed badly for visiting the state park. Instead, we headed up to Walhalla and toured the misty, scuddy and decidedly green Pembina River Gorge by car.
Ascending that small canyon, which drains an escarpment separating the Plains from the Red River of the North valley, leads the driver to the marvelously open, flat and attractive countryside characteristic of most of the state NE of the Missouri River. Folks here seem to inherit their ancestors’ fastidious tidiness ethic. In towns, this means well-kept houses, gardens and lawns. In rural areas, we saw a distinct absence of junk cars, rusty appliances, neglected fencing, or haphazard accumulations of dilapidated mechanical rubbish strewn across weedy lawns of occupied homes–in other words, a refreshign difference from thousands of points of blight that are prevalent in the southern Plains countryside. Landscapes here were familiar from the day before, but the setting was different–scuddy, light rain on the back side of the elevated storm band, with broken blue sky to the west, and the cool, moist freshness of wet earth behind a summertime cold front. This trip already was a splendid pleasure, and soon would become more so.
Proceeding westward across the borderlands, we finally broke into sunshine west of Langdon–but not for long! Onboard radar showed a thin, curving arc of cold-core thunderstorms developing to the W, over the turtle Mountains. A low-topped squall line was forming–something that experience told me could be quite photogenic in such otherwise clean air and sky. It was.
Approaching the squall line from the SE (as it moved quickly eastward), we marveled at how shallow and low-topped the convection was–typical for a cold-core low in a low-CAPE, relatively low-tropopause setting–but still rather uncommon in my southern-latitude experiences. In fact, just a few miles ahead of the arcus cloud, sunshine still illuminated the moist and richly verdant fields adjoining the east side of the Turtle Mountains. This clearly was not any of the 60,000-foot-deep walls of deep-convective severity I’m accustomed to observing in a North Texas April.
Our viewpoint was just SE of St. John, only four miles S of Canada, and in a fine position to view the oncoming shelf cloud. We were able to frame the sweeping arcus above the gentle curve of a rural dirt road that nicely split the greenery. After that, we cruised into St. John and let the storms move over us, enduring a decent barrage of small hail and subsevere gusts.
Heading into the hills, we quickly left behind the weakening squall line and visited the International Peace Garden (highly recommended, no passport needed!). The storms had run off the visitors, so we nearly had the place all to ourselves in rain-cooled air with sunny, late-afternoon light. Afterward, and with no one behind us in the customs line, I had a long, very friendly conversation with a customs officer and USAF vet at the re-entry station (the park is directly astride the border, its driveway halfway between U.S. and Canadian customs). He gave us a good recommendation for lodging options beside beautiful Lake Metigoshe–at which we reserved two nights for R&R before the next chase-worthy, northern-Plains shortwave.