May 10, 2011


Initial Target: Alexandria, MN
Departure: Chicago, IL 7:15 PM CDT May 9
Arrival: Hutchinson, MN 11:00 PM CDT
Intercepts: Foreston, MN
Tornadoes: 1
Hail: Severe (1.5 inch estimated)
Wind: Non-Severe (not measured)
Features: RFD Clear Slot, Wall Cloud, Mammatus
Miles: 806


Dryline/Warmfront play across central MN. Targeted afternoon triple point initiation near Alexandria, MN. Chased updraft towers struggling against the cap toward the St. Cloud area until storms finally matured near sunset. Intercepted sculpted supercell with striations, wall cloud, and large RFD clear slot east of Foreston, MN before getting stuck in the mud. Cored with severe hail as hook passed overhead while stuck, but was towed out within 40 minutes. Re-intercepted the slow moving storm after dark, but called off chase due to poor visibility and road grid, stopping in Hutchinson for the night.


Crew and Equipment:

Chase partners: Jennifer Brindley.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Millenicom 760 USB datacard and cradlepoint router, Holux 236 GPS, Robotic camera dome with Sony XR-520V. Canon 60D and EF-S 10-22mm

Photography courtesy: Jennifer Brindley


Tuesday, May 10, was to be the first chase in a two day marathon run out to Minnesota, then Kansas, and back for work on Thursday. The setup featured a dryline draped across western Minnesota that was forecast to track east during the day. Great shear profiles looked like they would favor supercells initiating off the dryline with the potential to produce tornadoes as they approached a warm front that extended southeast from a triple point in west central MN. The instability axis looked quite narrow, however, so there were concerns that storms would move into stable air before they had a chance to mature and produce tornadoes. There also looked like there might be some capping issues, so initiation was a concern, although the models did show the cap weakening and storms firing by evening.

Jennifer Brindley decided to team up with me for this chase. The target was west central MN just southeast of the triple point where we'd catch afternoon storms initiating off the dryline and hopefully catch a tornado as they'd move into the better directional shear along the warm front. We met up the night before in Milwaukee and decided to use my folks cabin in Montello as a launch pad for the chase as it put us a few hours closer to the target. We got up early and grabbed breakfast at Spark's cafe before making our way over to 94. The Storm Prediction Center kept the tornado probabilities quite low initially, which got our spirits down a little bit about making such a long haul, but after the morning update they upgraded the outlook.

We made great time through the rest of Wisconsin and were clear of Minneapolis by late morning. We continued up 94 making it to Alexandria where we decided to stop for lunch at Wendy's and check the data. A robust cumulus field was developing across the skinny warm sector and it looked like it might initiate at any minute.

Brindley and I packed up our lunch and headed down 94 south toward Osakis, exiting to watch towering cumulus going up. We were in perfect position to start chasing storms as they initiated. The towers went up but failed to stay up, before falling over and the convection going slack. We stayed until the initiating boundary passed overhead and we were in clear skies again before we started heading south and east to keep up with it. There was some lingering inhibition or lack of lift that was keeping the towers from maturing into thunderstorms, and we hoped that as the cap cooled and the better upper level energy arrived that we'd eventually get some storms.

Towering cumulus going up on the dryline and struggling to mature against the lingering capping:

Radar returns started appearing to our southeast and they looked better the further southeast you went so we started playing down the line, hopping from cell to cell. Storms developed anvils and the radar was showing them capable of producing hail, promising signs, but the anvils would go wispy as the updrafts continued to struggle. Cells to the north would die as they hit the stable air north of the warm front, and cells to the south were struggling against a stronger cap.

We jumped on a stronger cell with indicated hail near Albany and decided to track it northeast. It had a nice updraft base that even developed a nice horseshoe shape, but it was very elevated and it quickly started to fall apart. A storm just to our southeast was organizing rapidly with a severe thunderstorm warning. We made a dash south for the intercept. En route the cell started to develop a hook echo and went tornado warned. We got off of highway 10 near Foreston and ran east coming into the back side of the hook. It was dark underneath the base with turbulent white clouds above. We punched through the bottom of the hook, in a maneuver known as hook slicing, which was now a well known stunt for Brindley and I as we had gotten some of our most dramatic tornado views this year doing this manuever. This time, however, we found little in the way of observable structure. The rain free base, if there was one, was hidden by the precipitation core. We hit a smattering of severe hail too as we ran east to get ahead of the storm.
According to the radar, it looked like a flanking line storm was being pulled into the main cell, and that's when we got our first good view of an updraft base to our southwest. It looked scuddy and disorganized at first, but as it approached it rapidly organized into a barrel shaped mesocyclone. Near sun down it seemed like the ingredients were finally coming together for good supercells with the cap having burnt off and storms being able to mature long enough in the warm sector before they hit the warm front.

Just north of the hook echo, we started to move east with the storm, as a wall cloud started to develop on the northern edge of the barrel shaped meso's base. Isolated hail stones up an inch and a half were striking the van. We were using a well maintained gravel road to maintain our hook slicing position. Unfortunately, and just as the storm seemed to peak in intensity, our road turned to a big muddy slick with deep ruts. I didn't have time to react and we plowed right into the mud, with the front end starting to sink. I threw the van in reverse and tried to back out but we were stuck. The van seemed to give some so I tried rocking it, and got out and pushed on it while Brindley drove, getting drenched in the storm's core and sinking up to my ankles in mud. We were not getting out.


Barrel shaped, striated meso (top) with wall cloud (center/right) and large rear flanking downdraft cut (rear)

Rear flanking downdraft clear slot passing by to our south:

Looking overhead at some mammatus under the anvil:

Brindley and I got one last look at the storm as it slid by just to our south. We prayed it would produce a tornado right then, as we'd have a magnificent view of it out in open terrain, rather than in a few minutes, where we'd have no view of it as we were helplessly stuck in the mud.



The sky turned an otherworldly sepia tone as the setting sun filtered through the back end of the storm's hook. Everything was bathed in shades of brown light.

As the storm approached the warm front, it stalled and basically stopped right over our heads, leaving us caught in the precipitation core of the hook. Large hail started to ping off the roof of the van.

I pulled up Google maps and started looking for local towing companies to get a truck to pull the "Mudpuppy" out of the mud. I found a place in Milaca that had a truck they could send out to us. The guy on the phone was having trouble finding the dirt roads on his map and gave a hearty laugh when I tried to give him latitude and longitude coordinates of where we were stuck. He was less amused about what he could hear in the background though. "Is it...hailing there?" he asked. I told him we had some small hail coming down, but that it should be letting up soon and was moving south of town, hoping the storm wouldn't spook him from coming.

The storm was beast, however, with quarter to almost golfball sized hail coming down and for several long minutes. As the storm finally tapered off, the trucked arrived, hooked a long chain to the back of the van, and pulled us out of the mud, and all within 40 minutes. That has to be a personal time record for me calling a tow on a chase. Meanwhile the storm had only moved a few miles to the east. We could get back on it no time. We started heading east for the intercept, and we're coming in toward the back end of the storm, but night was setting in, and the road grid got real squirrely. Not wanting to tangle with an HP supercell, at night, and on crappy roads, we decided to call it a chase. We turned around and headed to Hutchinson for lodging for the night.


This was a fun first day out on a two day plains run. I was hoping it would be more of a "day before the day" type setup where Wednesday would be the bigger tornado play. We wound up scoring a nice sculpted supercell near dusk. I thought catastrophe had struck and we'd miss the show when we wound up getting stuck in the mud, but our storm never wound up producing any tornadoes and we had pretty much caught the storm when it peaked. Our quick recovery time getting out of the mud made the experience less of a disaster, as well. Given the low expectation going into the chase and the structure we caught, this chase was definitely a success for us.

Lessons Learned: 

  • Pay close attention to the road conditions when traveling on gravel, and slow down to make sure you can stop in time in case it changes.
  • Don't hook slice on gravel if there are paved roads near by that offer views just as good.