Chase Logs 2007
'It's Gonna be a Supercell Night': Lightning Explosion over WC MN
August 10-11, 2007
7:30pm (8/10)-11:30pm (8/11)
Miltona, MN
Well, it wasn't exactly a supercell night, but whenever severe weather threatens, my uncle Scott always proclaims "It's gonna be a supercell night!" I spent the past weekend at his (and my aunt Vicky's) cabin on the north side of Lake Miltona, about 15 miles north northeast of Alexandria, MN. The SPC 1300Z severe weather forecast that Friday morning called for a slight risk of severe weather extending along the Upper Mississippi River valley, but after numerous busts throughout the latter half of the summer, I was not impressed by this forecast. I only hauled up my DSLR to the cabin in hopes of capturing some meteors from the Perseid meteor shower, which would near its peak over the weekend. The drive up featured a hot and hazy sky devoid of any cloud cover. But at 7:00pm, high bands of cirrus floated over the lake, followed by a dark line of clouds to the west--a developing squall line. The encroaching line grew in size and cast shadows across the landscape as the sun was consumed by the storms. As evening set in, however, it appeared like high winds were shearing the tops of the thunderheads and I was heading for another bust. The first five photos below depict the developing squall line to the west in the late afternoon hours, while the second set of photos show the storms moving in front of the sun (first three) and then apparently weakening (last two over Lake Miltona).
Judging by the visual condition of the storms (I didn't have any internet connection available at the cabin), I decided that the storm front was dissipating and went inside to watch a movie at 8:30pm. Less than an hour later as twilight began to fade into the night, I decided to walk out onto the dock and check on the status of the storms. The southern end of the squall line appeared dormant, but to the northwest, through the tree-covered shoreline, I caught glances of flashes of lightning, even a stray C-G bolt. Intrigued by this new development, I unpacked the camera and tripod and set out after this new beast. The cabin sits at the bottom of a hill, flanked to the south by the lake and to the north by a 40-50 foot hill. To get into a good photo position, I had to trudge about 1/4 of a mile from the cabin, up the hill and down a dirt road. But the sight was incredible. The northern flank of the squall line had regenerated since sunset. It now loomed 15 miles to the north northwest, and spat powerful C-G lightning bolts in roughly 20 second intervals. I hurriedly erected my camera equipment along the road, and after a few test shots to nail down my focus, I began stalking the lightning with a 20 second exposure on f/4.3 using film speed of ISO 100. Like a child on his birthday, I yelled with excitement with each successful capture. The set of photos below need no explanation. . .
But my celebration was short-lived. Within twenty minutes of my first photo, I heard a dreaded sound echoing from the drought stricken corn stalks to my west. Rain. I picked up the tripod/camera, in the middle of an exposure, and ran back down the dirt road. Tiny wet spots began to appear on the dirt road behind me as I began the descent down the hill. I made it back to the cabin out of breath, but with the camera dry and safe. And as if the storm was mocking me, the rain never made it past the top of the hill. After an hour long break, I once again ventured out to the dock to capture another storm growing to the southwest. For the next 15 minutes another round of C-G lightning bolts ensued, allowing for some stunning photos of lightning over the lake (photos below). But out of the corner of my eye to the west, I saw an ominous lightning-illuminated rainshaft only a few miles away (last photo in set below). Not wanting anything to do with this rainshaft, I took a few photos of it before I headed back inside. Within 30 seconds, the downpour commenced.
Even with the torrential rainfall the C-G lightning bolts continued to the south across the lake. I set up the DSLR on the kitchen table and began to fire away. At 11:36pm the lightning storm began to intensify, unleashing a C-G bolt that struck the lake less than a mile away (first photo). Around midnight the lightning climaxed, dropping a series of C-G bolts several miles to the south (third photo) that rivaled my "Million Dollar" lightning photo over a year before. The only problem--the heavy rainsquall had coated the kitchen window with beads of water, which reflected the lightning flash and showed up on the photo. It will take me several weeks in Photoshop to try and remove them.
It was now quarter past midnight, and after a brief lull the lightning was revving up again. But this new round of lightning illuminated a new threat--a shelf cloud. The leading edge of an undoubtedly severe storm cell raced in from the west, bringing with it very strong winds and rain. The photos below capture the entrance of the of the shelf cloud, along with more C-G bolts, over a 5 minute window from 12:15am-12:20am.
Within five minutes of the shelf cloud's passage, a rain curtain flooded the lake, ending my lightning chances for the night. Still, the omnipresent lightning flash bulbs and high winds kept me awake until 1:00am. The morning revealed an awashed landscape. Low scud clouds raced over a glass lake; the trailing fringes of the previous night's storm. Even a rainbow briefly appeared to the west. The beach suffered some erosion from the 2.5 inches of rain measured by the rain gauge on the dock. But the most impressive sight was my dad's fishing boat, moored to the dock. The high winds and waves overnight had caused the front mooring lines to part, but thankfully the backup midship and aft lines held. The combination of waves breaking over the stern of the boat and the excessive rainfall had flooded the stern of the boat in up to 6 inches of water above the bilge (which was another 1-2 inches deeper than the deck). The boat settled by the stern and took a starboard list, due to the gas tanks and motor on the stern. Thankfully the battery terminals remained above water and we were able to start the onboard pump, which removed the water in about 20 minutes.
Stray rainshowers plagued the morning hours, but by noon the skies were clearing and my dad and I went fishing. A few rumbles of thunder echoed across the lake, but nothing substantial formed. Shortly after dinner three storm cells developed within eyesight of the lake, one to the east, one to the southeast, and a final cell to the south. The eastern storm formed a solid anvil, but drifted out of sight within the hour. The two remaining cells cycled several times throughout the late afternoon, with both cells reaching a peak intensity shortly after 8pm (from a visual standpoint only). By the time the sun set, both storms were still clearly visible, even though the SE storm was over Hinckley and the southern storm was located over Minneapolis (over 120 miles away!). All of the photos below are of the southern cell. The cells glowed pink with the setting sun, and as twilight set in they erupted in a fireball of lightning (last three photos in second row). This light show lasted well into the night. . .
August 12 Update: Below are photos taken of the storm damage at my house from the August 11 storm complex. We only had a few large branches down (first photo), but the neighbors to the west lost one of the trees in their front yard.
The weather station only measured a sustained wind speed of 44mph that morning.
