The first cell quickly formed literally on the Canadian border near the corner with Montana and began to track east, it looked nice but was just too far away. A second cell formed west of Minot, ND developing the telltale highly sheared supercell structure on radar and we quickly closed to approach it north of Minot.
On first glance we were a little surprised in the elevation of the base, but its a long way for the moisture to come from the gulf of Mexico up here. Still, the cell was nicely structured, and had some severe hail (1.25 inch, 3 cm) along with reasonable rotation.
|The main area of rotation was overhead and a white cone formed briefly. Photo - Brad.|
|The dynamic motion was impressive but the supercell was just gearing up. Photo - John.|
It tried a few times to produce more substantial wall clouds, but it wasn't until it approached the Canadian border that it really dropped down and formed a strong tailcloud and wall cloud right in front of us, after most chasers had bailed south.
|The storm ramps up with a spectacular tail cloud structure as we race alongside. Photo - Brad.|
Shortly thereafter in the distance in fading light we saw what we believed to be a tornado just over the border with Canada. Unfortunately the distance from us when it finally decided to happen made really difficult to really get what we were looking for, but the structure was definitely worth the effort.
One of the more odd aspects of the day was when a Customs and Border Protection agent pulled up to ask what we were up to (about 10 miles from the border) right after we observed the possible tornado. He mentioned that if we were looking for something to photograph that he saw a Moose on the road about a mile from us, before we explained we were chasing storms, much to his amusement. Still, on another day the same system might have produced tornado after tornado...even on the particular day you are never really quite sure what you will get dished up with.
Its interesting that 2 years ago on this date (May 22), a cell in a slightly more moist environment in northern South Dakota produced a violent tornado near Bowdle. Stepping back to last year, a cell produced the Joplin EF-5 tornado which killed 162 people. Its funny how particular dates seem to produce these powerful storms more often than not, it does make you wonder whether its just our nature to see patterns or whether there is really something to it. I guess missing the Bowdle stormwhen chasing here 2 years ago made us more hestitant to not make the long drive as we really didn't want to have that happen again. When in comes to the thunderstorm environments, the differences can be quite minute but the results poles apart, which makes it interesting to look at the similarities with historical events and the climatology.