The “my first tornado” meme circulating on Facebook prompted me to dust off my first chase log book and relive the Benson, Minnesota tornado – my first ever. I kept an astonishing amount of detail, and it helped me reconstruct the chase. On subsequent chases, I’ve usually been in the driver’s seat and not kept such detailed logs. But when you’re packed in the back of a van with a dozen other students, there’s not much else to do besides observe and record.
In spring 2001, I had a freshly-printed B.S. diploma from the University of Wisconsin – Madison’s Atmospheric and Oceanic Science department in hand, and taken a job as a research intern at the Space Science & Engineering Center on Dayton St. I decided to enroll (as a “super senior”) in the biennial summer course AOS 455: Severe Storms Forecasting, taught by Dr. Greg Tripoli. After a couple of weeks in the classroom reviewing mesoscale meteorology, we piled into two white university vans and spent 10 days cruising the Great Plains, chasing turkey towers with Josh Wurman & Co. (who were then rolling in DOW2 and DOW3), sampling the local cuisine (ahem, Taco Tico), pushing the vans out of the greasy red mud, and taking in local sights (e.g., “No trespassing” signs riddled with bullet holes, and a storage facility eloquently named U-STUF-IT). This newly-minted meteorologist from the Midwest found plenty of warmth and charm in the rolling Plains. I distinctly remember watching majestic bubbling cumulus from a parking lot in Harper, Kansas one afternoon, surrounded by fields of waving wheat. I took a deep breath of balmy Gulf air, felt the wind tickle my short hair, and thought to myself, “You know, I could get used to this.”
Near the end of our trip, we migrated back north along I-35 in preparation for our return to Madison. It being early June, the jet stream had begun to migrate north as well. We started off the morning of 11 June in Rochester, Minnesota, and headed north toward St. Cloud. A surface low tracked across northern MN, dragging a cold front behind it, we anticipated the latter would touch off a round of storms in western MN. Wind profiles were marginal, but the air was sticky (72+ F dewpoints, thanks to the exhalations of the corn crop). We banked on the storms generating their own environment.
We stopped for a couple of hours near Olivia, MN, watching backbuilding pulse storms fire off and scoot by to our north. One by one, they marched away to the east like lemmings and collapsed, much to the consternation of our green group of storm chasers, who were straining at the leash to chase something.
Finally, a new storm west of Willmar began to look better organized. A pay phone call from Dr. Tripoli to nowcasters back in Madison confirmed that was our target. We headed west on U.S. Hwy. 12. As we approached Benson, MN from the east, at around 2015 UTC, we observed a rain-wrapped wall cloud. From our vantage point about 20 miles from Benson, the rain cleared, and in the peach back light of the late afternoon sun, we saw a cloud appendage with a persistent dust whirl beneath it. I had my VHF HT hooked to my belt, and could hear local spotters confirming a tornado in the direction we were looking. I snapped a few pictures before we got back in the van to follow the storm.
We observed a few more wall cloud cycles and dust clouds as we followed the storm back towards Willmar. Tornado warnings followed the storm too, but we never spotted another funnel or tornado. The Benson storm eventually outran us, and we abandoned the chase near Glencoe. I remember making a collect call from a gas station pay phone to my parents in St. Paul, warning them about the approaching hailer. (It did eventually evolve into a mini-bow as it passed over the Twin Cities, and left a fat swath of wind reports across western Wisconsin.) I can’t remember if we drove all the way back to Madison that night or not, but my log book doesn’t have another entry until 14 June.