Chase Logs 2007
Outsmarting the Twister: The Northwood, ND Tornado Supercell
August 26, 2007
5:30pm-11:45pm
Grand Forks County, NDVideo from the Northwood, ND Supercell Chase
I couldn't have asked for a better storm setup. A classic heat wave/cap, a classic supercell line, and unfortunately, a classic deadly tornado. In advance of a potent cold front the temperature and dewpoint in eastern North Dakota shot into the low 90's and 70's, respectively, late this morning. Storms began initiating along the cold front along a line from Bismarck to Devils Lake shortly after 5:30pm and attained severe status at 6:00pm. By 6:15pm, three distinct cells had formed along this line. After debating for some time on which storm to chase, I loaded up the car with the entire camera arsenal at 6:40pm and headed west on US HW 2 to intercept what I thought was the most potent cell located about 50 miles due west. The anvil of the storm extended a good 30 miles in front of the updraft and was already obscuring the sun in Grand Forks. A nice set of crepuscular rays flooded the western skies in between the center and northern updraft towers as I passed the air force base at 7:00pm. I called Dan to get an update on the storm's motion as I pulled to the side of the road to snap a few photos of the towers (photos below). He relayed that the storm had started hooking to the right--changing its course from ENE to E, meaning that I would be sitting on the north end of the storm instead of the south like I had initially planned.
In my rush to leave UND, I forgot to purchase a map of the state since I hadn't ever chased in ND before (I did have my MN map on me--little help that was). Despite breaking my golden rule of storm chasing, I decided to turn south on a dirt county road to get to the other side of the storm. I must of had something bad for dinner, because that was one of more stupid decisions I've made on a chase. Good thing the storm was still far away. I barreled south and east down the network of roads, hoping to run into a marked road. I stopped several times along the way to take photos of the storm's base (below) and call Dan to obtain updates to the storm. By now the storm's anvil was covered the entire sky while scud raced a few hundred feet overhead. Strong lightning bolts crawled along the underside of the anvil.
After my 20 minute roller coaster ride on the backroads, I finally found a paved N-S road and floored it south. At 7:30pm I turned west on ND Highway 15 and moved a few miles to the west before pulling over on a field access road to take some video of the storm (roughly 4-5 miles east of Northwood). By now the cell was located about 20 miles to the west and was producing constant C-C and C-G lightning bolts. A few minutes later (7:40pm) I observed a small lowering in the clouds in a clearing straight down the highway, but I dismissed them as scud and continued to film the storm's structure/lightning. The cloud moved behind a treeline less than a minute later. Whether or not it was tornadic is still a mystery. Dan and I once again conversed via cell phone just before 8:00pm, during which I found out that he had moved to the west end of Grand Forks along with Matt to watch the storm, but he relayed a doppler detected tornado warning for Grand Forks County. The tornado was reported to be 25 miles west of my current location, moving east. I could not pick up any radio signal from my weather radio.
With the storm growing less and less defined with the fading sunlight, and the possibility of me being in the path of this twister, I decided to pull out, fast. With the first rain showers I packed up the camcorder and flew east on ND 15; lightning crawled over the clouds above me, its thunder shaking the frame of the car. Going 85mph, I was able to reach Thompson (20 miles away) in less than 15 minutes. Here I pulled off on a dirt side road and filmed the oncoming storm while at the same time placing another call to Dan, who was retreating to a UND Aerospace complex building as the storm neared Grand Forks. A few more minutes of lightning taping ensued before the rain squall caught up to me again. With no radar imagery, maps, or sunlight to guide me around the storm, I made a conservative gut call to head back into Grand Forks to seek shelter from the storm. I cruised northward up I-29 and made it back into Grand Forks shortly after 8:30pm.
I met up with Dan, Matt, and Laura in the Studio One loading dock, a favorite local storm watching spot for Dan and I in years past. I got all of my equipment inside just as the first wave of showers moved in. With the wind out of the SSW, it was hard to shoot any lightning photos outside the doors, but I managed to capture two nice bolts with the DSLR (photos below). The real story, however, was the hook echo developing just west of Northwood. We used the S1 computers to track the stunning hook as it passed over Northwood at 8:50pm. After the hook dissipated east of Northwood, we decided to move to Dakota Hall to get a better position on the storm. By now the brunt of the storm was upon Grand Forks, unleashing torrential rains and winds over 40mph. After a drenching run to the cars, we crawled up 43rd St., dodging tree branches and areas of standing water.
We stood under the front eve of the hall for a few minutes until the tornado sirens began wailing, at which time we moved to Dan's room to track the cell. After sitting in the room for 15 minutes, Dan and I ventured outside and collected a hailstone in the lawn, measured it at 0.75 inches, and called it into the weather service. We were back under the front eve of Dakota ten minutes later watching the departing storm's lightning show and gawking at the standing water on 43rd St. After a show of strobe lights in the sky, I noticed a large field of mammatus clouds covering the sky above us. I packed the camcorder and hauled out the DSLR, and for the next ten minutes the camera's shutter fired non-stop. The storm continued its trek into Minnesota, and at 10:20pm Matt and Laura left for their homes.
But shortly thereafter, a second line of storms formed just south of Thompson along the outflow boundary of the first storm, leading to a spectacular lightning display. I was sitting in my room watching the afternoon's video and getting ready for bed (I had an 8:00am class the next morning), but after a few C-G bolts dropped nearby I decided to call Dan and head out to the Dakota parking lot for some photos. By 11:45pm the cell was beginning to move out of range, revealing a full moon to the south. Quite a beautiful sight, with the moon and lightning together. An additional cell formed again along the outflow boundary at 12:30am, but I did not take any photos of it.
At 2:00 that afternoon (8/26), I activated my severe weather operating system and began tracking any cells that may develop over North Dakota, and left the system running during my chase. Combined with the radar products from the NCDC, I obtained about 500mb worth of raw radar data from this event. Below are some of the images WeatherScope recorded while I was out in the field. The top four images are base reflectivity scans of hook echoes in the cell I chased taken from KMVX at (from left to right): 8:02pm, 8:23pm, 8:49pm (tornado over Northwood), and 8:57pm. The five velocity scans below the first set of images are from: 8:02pm, 8:32pm, 8:40pm, 8:49pm, and 9:22pm. These five images distinctly show the rotation signature of the storm as it traverses southern Grand Forks County.
The following afternoon (8/27) I traveled to Northwood to witness the damage of the tornado firsthand with Steve as part of a story for Studio One. Our status as members of the press allowed into the town to take footage of the damage and clean-up efforts. The experience is one that I will never forget. It is one thing to view the damage on TV, but to be walking through the rubble and watching people sort through the remains of their houses was truly heartbreaking. Filming the devastation and people who's lives were forever altered by it, without being able to lift a finger to help, was one of the hardest tasks I have ever embarked on. I did not take my digital camera into town, but I did take some photos outside of the quarantined area which show the worst of the damage to a grove of trees and a building along ND 15. Maybe sometime I will be able to post the footage I shot. The photos speak for themselves. . .
By Tuesday, August 28, the tornado survey by the NWS was complete. The Northwood tornado was rates as an EF4 with winds of 170mph, the latest EF4 in the history of North Dakota. The track of the tornado stretched for five miles while its maximum width reached an impressive 8/10 of a mile. One fatality was attributed to the tornado, which occurred when the tornado passed over the mobile home park on the NE edge of the city. Damage estimates at this time are around 50 million dollars. Below is a plot that I made of the track of the tornado. This is by no means an official track, but I compiled data from my visit along with NWS survey statistics to create this map. The white line represents the track of the tornado, while the yellow line tangent to the white line (just SW of Northwood) illustrates the width of the tornado.
In retrospect, this storm chase set many milestones for me. This was the first time I had ever left the confines of Grand Forks to storm chase in North Dakota. It was the first time I had ever chased a full-fledged supercell; I am more used to chasing cell clusters or squall lines, which are must more common in the Upper Midwest. It was the first time I had intercepted a storm that produced a major tornado. It was the first time I intercepted a storm that leveled a town and caused fatalities.
