Bradgate Iowa Tornado
May 21, 2004 Chase Report: Bradgate, Iowa Tornadic Storm
I started the day in Des Moines, Iowa. A significant severe weather outbreak
was expected with a moderate risk across Iowa. Determining a target was
difficult as storms could fire anywhere along the warm front or even along the
dryline to the southwest. Areas of interest included north of Des Moines and in
northeast Nebraska. I checked data with Jeff Piotrowski and we finally decided to
head north and then west. Interestingly, there was a bull’s eye of low LCL’s
to the northeast. At 1:28PM, we turned west from I-35 toward Fort Dodge. We
were approaching a small storm heading east and it was producing some hail. We
stopped briefly to observe the storm but it didn’t appear that good visually.
The storm appeared outflowish. We decided to blow it off and continue to the
target area. We drove through the storm and encountered some small hail.
Approximately 30 miles east, the storm along with a nearby storm, became
tornado-warned. Arrghhh! We stopped and considered blasting back east. I didn’t think
these storms would hold together and we would have better storms later in the
day at the target area. We continued west and then watched the storms produce
multiple tornadoes on the XM receiver. Jeff received a report that a news
helicopter was flying around a tornado and sending back live images. I was really
depressed. We stopped several times to check data. The storms east were to far
to catch. By 4:21PM, we were approaching Sac City on state road 20. Storms
were forming to our northwest near Cherokee and another was to our west. The
appeared mushy and soft. Further west in Nebraska, winds were still from the
southwest in our target area. We turned north at 4:45PM on 71 and headed toward
Storm Lake. Storms were developing to the east of the town. The storms to our
north then developed multiple cores. Visually, they appeared outflow dominated.
We stopped to get gas and considered blowing off the mass of cores to the
north. Then, one area began to develop shear by 5:15 PM. We blasted north and
briefly saw a wall and tail cloud.
First wall cloud: 5:28PM
http://www.harkphoto.com/tempwall1052104.jpg
We continued north and the wall cloud elongated as the core approached. We
were on the southern storm of a developing massive complex of storms. Shear
decreased on the XM. A new area of shear appeared to the northeast at 5:30PM. We
turned east on 10 then followed the storm east on 3. The storm was to our
north and moving east.
Second wall cloud: 6:11PM
http://www.harkphoto.com/tempwall2052104.jpg
By 6:05PM, we received a report of a couplet on radar. At 6:07PM, we drove
through Pocahontas. I could see some rotation through the trees. At 6:08PM a
tornado warning was issued for the storm. To the north, I could see rapid cloud
motion and rotation in two areas at 6:12PM. The storm appeared linear with
the forward portion somewhat bowl-shaped at 6:13PM.
Storm to the north: 6:13PM
http://www.harkphoto.com/tempstorm052104.jpg
The whole storm was rotating. We continued east and at 6:16PM, we stopped a
saw a tornado to the north. It was behind the precipitation that was wrapping
around the edge of the storm.
Tornado (wide shot): 6:16PM
http://www.harkphoto.com/temptorndist052104.jpg
Tornado (zoomed): 6:16PM
http://www.harkphoto.com/temptorn052104.jpg
Brief needle tornado, lower part not visible on video still but is on video.
On review of the video, a brief dust whirl on the ground is visible: 6:20PM
http://www.harkphoto.com/tempneedlefunnel.jpg
Weird twisted area of rotation: 6:24PM
http://www.harkphoto.com/tempweirdvortex052104.jpg
The storm kept cycling and at 6:20PM we saw violent rotation of the cloud
base and a brief twisted narrow funnel on the edge of the storm. A weird twisted
area of rotation formed at 6:24PM. We entered the town of Gilmore City at
6:24PM as the tornado sirens were blasting. The streets were empty. We followed
the storm eastward and it developed a nice inflow feature. Hooks appeared and
vanished on radar through the whole period. Cold air eventually started to
enter the storm and it died. We left the storm as darkness approached.
Inflow feature
http://www.harkphoto.com/tempinflowfeature052104.jpg
Edge of the storm
http://www.harkphoto.com/tempedgestorm052104.jpg
Cloud to Ground Lightning
http://www.harkphoto.com/tempcg052104.jpg
Unfortunately, we later heard that the town of Bradgate (a few miles to the
north of Gilmore City) was seriously damaged by the tornado from this storm.
Injuries were reported. The drive west to South Sioux City, South Dakota was
wild as the sky flashed with lightning. The lightning was constant and I
probably could have driven without headlights. Frequent CG’s (cloud to ground
lightning) stuck the ground as the background flashed. I am now checking data for a
possible severe weather outbreak Saturday.
William T. Hark
http://www.harkphoto.com
