Summary of Roundup, MT Supercell
(written by my chase partner Vince Miller)
What a day! Mike and I figured we would be at the rest stop west of
Miles City for at least 3-4 hours; it turned out to be 6. A line of Cu
to our NW to far W occasionally percolated during the late afternoon,
but was never able to sustain any long-lasting updrafts. About 6:30
p.m. MDT we left the rest area and drove 20 miles west to Forsyth,
keeping an eye on a area of Cu to the N which finally was achieving
some success at staying alive. A quick bite to eat was followed by the
decision to head WNW on US-12 to intercept supercells which were well
to the WSW of Roundup, while at the same time keeping an eye on the TCu
to our N which were showing serious attempts at punching into higher
levels of the atmosphere. The atmosphere punched back, however, and the
TCu rapidly became turkeys.
By the time we reached Ingomar (about 7:45 p.m.), the sun was just
disappearing behind the anvil of one of the supercells to the WSW. We
made a quick stop to take pictures and noted the winds were strong and
gusty from the north. As we drove a bit further W we were rewarded with
even better views of the backsheared anvil and a nice vertical wall on
the S side of the storm. Shortly afterwards, we were treated to a view
of a distant flared base (not of the southern most supercell}, and then
a complete view (and what a view) of the distant southernmost
supercell. We found a place to pull off the road to take pictures
(about 8:15 p.m.); our vantage point was 42 miles ENE of Roundup
(between Melstone and Sumatra). We decided to stay put because the
structure of the storms was fantastic. [Mike took many pictures over
the next 30+ minutes; I took some pictures and also time-lapsed the
storm during the same period. Our picture taking and time-lapsing
covers the time 4.25" diameter hail was reported at Roundup. Mike also
has some zoomed in photos of what may be a funnel; his photos are
within several minutes of the time of the funnel report near Roundup on
a Billings PNS statement.] The southern most storm had explosive growth
on its SE side during this time; we decided to backtrack to the east to
get a better vantage point for structure shots, and also because
lightning was becoming a distinct threat.
We stopped in Ingomar (a ghost town at best) for photography
purposes; storm structure was incredible, and lightning was increasing.
We had to abandon the picture taking after a while because of lightning
danger; so more backtracking to try to get ahead of the storm for more
structure shots and to get away from the lightning danger. During the
next 23 miles to the SE to Vananda we were treated to not only one
"mucho-supremo butt kicking storm", but also to a barrages of CG’s from
the storm’s anvil. Mike took some excellent hand-held photos of the
storm/lightning as we raced down the highway, and also some video on my
VX-2000.
We stopped in Vananda (another town which long ago lost whatever life
it had) so Mike could take some more structure shots – a dicey
undertaking by now. But, thankfully, the sparks from Thor’s hammer
stayed away from our immediate vicinity.
More backtracking towards Forsyth; we may or may not have seen a funnel
back-lit by lightning; we stopped several more times to take lightning
photos, and finally made it back to Miles City and the same motel where
we spent the previous night.
Vince Miller