MPR’s Lorna Benson interviews WCCO meteorologist Paul Douglas, who says the massive storm system on July 25, 2000 was unusual in a number of ways. For one thing, it produced many more tornado warnings than usual in Minnesota.
13 tornadoes were confirmed in Minnesota on July 25, 2000. The most devastating traveled nine miles through parts of Yellow Medicine County and hit portions of Granite Falls, causing destruction of 41 houses, 300 damaged buildings, and one fatality. The damage in Granite Falls was caused by F2 and F3 winds speeds, with a tornado being classified a minimal F4 based on the twisted wreckage of an overturned railroad car.
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SPEAKER 2: I felt for a time like I was doing the weather in Tulsa or Wichita or Dallas. We're not used to getting a couple of dozen tornado warnings for a couple of dozen Minnesota counties in one evening, especially fairly late in the season this far North, but it was somewhat reminiscent. We had flashbacks of Saint Peter in terms of the severity of the storms and the fact that these things were holding together hour after hour.
So I think the number of tornado warnings was unusual, as was the severity of the storms and the fact that these things just kept on going right up into the Twin Cities. We had funnel cloud sightings over Golden Valley and Minnetonka.
SPEAKER 1: What classification do you think that the storm that hit Granite Falls was?
SPEAKER 2: It's still a little bit early to try to classify these. The National Weather Service sends teams out that inspect the damage and based on the severity of the damage, that is how these tornadoes ultimately get their rating. It scale from 0 to 5, 0 is a minimal tornado, an F5 is what hit Oklahoma City a couple of years ago, producing total devastation.
The vast, vast majority of Minnesota tornadoes are F0 and F1. Just based on the damage that I've seen, some of the aerial imagery from my helicopters, this thing looked like it was half a mile wide at times. Hundreds of homes damaged, destroyed in Granite Falls. My hunch is that it was at least an F2, possibly an F3, which would make it as strong as the tornado that hit Saint Peter a number of years ago.
That would imply winds approaching 200 miles an hour. Even well-constructed brick homes are not going to be able to withstand 200 mile an hour winds.
SPEAKER 1: Last night I was on the air doing some of these warnings, and the National Weather Service warning did not come across my computer screen until about 6:19 which, as I understand it, this tornado was on the ground in Granite Falls at that point. But sirens had been going off in Granite Falls, as I understand it, for about 20 minutes. So what accounts for that discrepancy?
SPEAKER 2: At a county level, civil defense directors in each County of Minnesota have the option and have the power to be able to sound the sirens independently of what the National Weather Service is doing. And I think that's probably a good thing. Since they're there, they're looking at the weather, they're in the weather.
The problem is our technology, the National Weather Service Doppler radar and our own Doppler radar at Channel 4, they're great. They can't pick up individual tornadoes. We don't have the resolution to actually go down and pick up something that's half a mile wide over Granite Falls. All we can do is say, here is a thunderstorm that is rotating.
And then roughly 30% of these rotating thunderstorms do go on to drop a tornado, but there is no substitute to having people on the ground literally out in the field confirming that, in fact, this spinning thunderstorm is dropping a tornado. And so we did have a number of reports, and I think that helped to certainly minimize the death toll and the number of injuries and the fact that there was, in fact, some warning.