MPR’s Mark Heistad interviews meteorologist James Campbell about the storm that parked over the Twin Cities, bringing torrential rain and a tornado. Campbell describes it as a 100-year event.
Considered the Twin Cities “Superstorm,” the July 23-24, 1987 event dropped 9.15 inches at the Minneapolis–Saint Paul International Airport, and over 10 inches in suburbs west and southwest of Minneapolis. This rainfall cataclysm produced the worst flash-flooding on record in the Twin Cities. A tornado touched down in Maple Grove.
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MARK: Jim Campbell is with us live now from the National Weather Service office here in the Twin Cities. Good morning Jim.
JIM CAMPBELL: Good morning, Mark.
MARK: I have to ask. First off, a real basic question. What in heaven's name happened last night? 10, 12 inches of rain around the Twin cities? Tornadoes reports of twisters throughout the Twin Cities. Tell me about this storm.
JIM CAMPBELL: Well, we had an incredible night. And one of those things that probably happens once every 100 years or something like that. What happened was the meteorological situation is that we had two air masses that were essentially clashing with each other. We had an air mass down to the Southeast of us. That was a very warm and humid air mass, pumping a lot of moisture up into our area. And then up North of us, we had another air mass of a little bit cooler and drier air, and we had a front in between the two air masses.
And essentially what happened is those two air masses that front stagnated right over the Twin Cities area. And as a result, pumping all that moisture in and the conditions were right for both severe weather and heavy rainfall. And so the result of that was the one tornado that we had in Maple Grove. And of course, as you said, the 10 to 12 inches of rain around the Twin Cities area. In fact, we broke the all time record here at the airport. We had 10 inches of rain, and that broke the old record of 7.80 inches. That was established back on July 26 and 27th in 1892.
MARK: So it was indeed just one storm that stalled over the Cities and just dumped rain all night.
JIM CAMPBELL: Well, it wasn't really one storm. What happens in a situation like this is you get a series of storms. Most of the storms were moving from West to East, and you just get a whole slew of storms moving across the same area. We call it the terrain effect, essentially. And that's what was happening last night. We just had thunderstorms continually moving across the same area all night long.
MARK: Now, I wonder about twisters and tornadoes, what confirmation you have on how many of them we had in the Twin Cities last night?
JIM CAMPBELL: Well, at this point, the major one we had was at Maple Grove. Of course, there was a lot of damage out there. We haven't had a chance to either get out and look, or get a good idea that it looks like there might have been another small tornado up in the Brooklyn Park area. Around 7:00, there were a couple of houses damaged up there. We had just numerous reports of funnel clouds and of rotating wall clouds, which are the precursors of tornadoes from spotters and law enforcement people all over the area.
So in some senses, we were-- it was a very strong situation, and we were lucky to get out with just the one tornado that we had. I'm surprised that we actually didn't have some more and even some stronger tornadoes during those early evening hours before the heavy rain started.
MARK: One of the things that impressed me as I was listening to coverage last night of the storm, we would hear about a twister sighted, but not on the ground somewhere out in the Western suburbs, and then at the same time, somewhere in the Eastern suburbs of the Twin Cities. The storm had to be massive in terms of its size. It was so large.
JIM CAMPBELL: Yeah it was-- there were a number of thunderstorms mixed in with all that. And Yeah, there was severe weather all the way across the seven County metro area. And it was very, very slowly moving, coming down from the North and then pretty much stalled out over the city. And that's when our heavy rains began. But I know even here at The Weather office, we were looking outside our window and it looked pretty awesome and pretty dark outside.
MARK: Nothing of on tap for today, I guess, though. It's all over.
JIM CAMPBELL: I think it's all over. We do have a little chance of maybe a thunder shower late today or something like that. But certainly nothing like what happened last night.
MARK: Well, one more question then we'll let you go, get back to your work here. Where-- the storm went what, South through the Twin cities Southeast? Where did it go from here. And what happened? Did it die out?
JIM CAMPBELL: As it moved through the Twin cities, it moves through some of our Southern counties and got into the Rochester area, but it began to move a little bit faster. And the rain intensity slacked off somewhat. And so really the biggest area for the rainfall and the severe weather was right here in the Twin Cities.
MARK: Well, we sure got it. Jim Campbell, chief meteorologist with the National Weather Service. Thanks so much for being with us. We appreciate it. Take care.