Eau Claire County
|I screwed up. Yup, I said it. I SCREWED UP.
One of my golden rules of chasing is "if there isn't definitive video or stills to prove it, it didn't happen". Well, what happened and what we saw in Augusta, Wisconsin this day fits right into that category. With this being said, take the rest of this chase account for what it is worth.
|I'm going to look at this chase accounts as more of a "why" than a "what". After the huge night in Iowa, the 10th was shaping up to be another day with a lot of potential for tornadoes again as a surface low tracked out of east central Minnesota into northwestern Wisconsin. My initial target was the I94 corridor on the MN/WI border with the idea of getting downstream of the storms as they fired off to the southwest and let them mature as they approached. After discussing with my usual chase partner, David Drufke, I felt confindent in the choice and I94 would allow us to rapidly adjust as the storms would be moving 50-70 mph off to the northeast. Myself, Cullen, Cailyn, and Matt Beckers departed home about 11:30 in the morning knowing it would be an early and very short show.|
|Right off the bat I knew we were in trouble in terms of good tornado potential as the winds veered from the southeast rapidly to the southwest out in front of the cold front. The better southeasterly winds would remain further east well into Wisconsin. We opted to head east towards Menomonie and allow the first storm which fired near Red Wing, MN to race up to our location. This storm looked AWFUL visually with a long skinny updraft base being stretched by the unidirectional southwesterly winds up through the atmosphere.|
|Here is the watch product issued by the Storm Prediction Center.|
|After bouncing off a couple of more cells which also looked like junk, we dove southeast through Eau Claire and pulled off of I94 at Foster, WI to watch much better looking storm which was obviously becoming a supercell. The storm quickly went severe then tornado warned based on radar. Note the location of Augusta in the center of the map.|
|Note the strong couplet starting to develop in the hook of the cell. Also notice the other cell to the south near Osseo has some strong wind fields associated with it. These two cells are not moving at extactly the same vector and are on a collsion course which will allow them to merge at some point. Splits and mergers on supercells are pretty common but the event about to happen over northeastern Eau Claire county is a little more uncommon.|
|Just piror to the merger now.|
|SRV showing the crazy wind fields developing jsut to the west / southwest of Augusta.|
|Immediately after the collision / merger. Radar fold is a real problem in this area.|
|From our vantage point on county road V west of Augusta and north of Foster. To the best of our knowledge this feature never touched down. A spotter to our southwest reported this as a funnel but it was very short lived.|
|Looking a little better now and starting to get excited.|
|..and it's gone. This sequece of shots was less than 3 minutes.|
|David Drufke getting a better view from up top.|
|We flew east towards Augusta and stopped just west of town as the northern supercell had a well defined inflow notch with a cascading rear flank downdraft producing strong rotation nearly right over head. The meso of the southern cell is racing up from the southeast and is headed basically for the inflow notch of this cell.|
|And the cells merge over Augusta. At this time Matt Beckers alarmedly pointed our attention to the city of Augusta now just 2 or so miles to our east. There in a field just to the east of the highschool, there was a very small but very intense vortex hurling brown dirt and debris a couple of hundred feet into the air and FLYING off to the northeast on what looked to be the very northern edge of town then BANG. It was gone. Just a fast as it appeared under the area of rotation it dissappeared. Caught flat footed. While trying to position ourselves for a shot, it dissipated to nothing but dirt falling back to earth along with small pieces of debris. It wasn't outflow or RFD as it was moving the wrong direction. It was also VERY narrow. Maybe only 100 feet (at most) across. We raced east towards town and were met by sheriff's deputies also combing that same area for damage or injuries. Lots of tree debris, snapped power poles, and twisted metal stuck up in other trees and wrapped around power poles and wires. I called the National Weather Service in Chanhassan, MN at this point to inform them "something" had hit the north end of Augusta.|
|My daughter Cailyn looks out in amazement at all the damage this little "spin up" caused as David and his wife, Kristen, follow us through the damage path heading north on highway 27 in a feeble attempt to stay with the storm now rocketing off to the northeast into the pine woods at over 60 mph. After a few miles we gave up as there were no road options which would allow us to make up time to get back into the chase. We headed back to Augusta only to find the city sealed off by the fire department due to the damage including downed power lines which were causing fires in the town. We decided the best thing to do was circumvent the town by staying west and heading for home. As we headed south down county road R, we witnessed A LOT of structural damage but it all appeared to be the result of straight line winds. Trees down, barns toppled, partial roofs off, etc.
On the way back, I chatted on the phone with my friend, John Wetter, who was at the National Weather Service to give him some more details of what had just occurred. He sounded like there would be a damage survey. Since I had no photos or video of what we saw hit Augusta, I knew the best thing to do was to keep my mouth closed and let the experts from the NWS determine what happpend. Here are those results from the damage survery completed April 11th by Matt Friedlein from the NWS MPX office.
|Interesting thing to point out here is the "sensor". There was a weather station at a DNR maintenance facility on the east side of 27 which somehow avoided all the debris and the vortex which demolished the facility. About as good of info as can be obtained.|
|What a crazy day....and a non-textbook storm.|