How damage in Fairfield was used to estimate 120 mph wind speeds from Sunday morning severe weather

FAIRFIELD, N.D. (KFYR) - The damage in Golden Valley and Billings Counties was widespread after the weekend storms, and there’s a process that’s used to determine how strong the winds were.

Severe weather moved through North Dakota early Sunday morning, but it wasn’t until after the storms that wind speeds were estimated to be 120 miles per hour near Fairfield.

Based on radar signatures, meteorologists could tell that the storm was very strong in the Beach and Fairfield area. That’s why a severe thunderstorm warning with the destructive tag was issued for the region, meaning that winds would be at least 80 miles per hour. This is the highest category for a severe thunderstorm warning which triggers a wireless emergency alert on your phone.

But after the storms, meteorologists at the National Weather Service gathered photos and talked to emergency managers and electric providers to match up the damage with a list of indicators to estimate the winds.

“We have 28 different damage indicators. Ranges from school buildings to small homes to towers. So, in this case, the ones that really stuck out with damage, we had a communications tower that was 120 feet tall that fell over and we had 100 electrical poles that were broken,” said Jeff Schild, a senior forecaster at the Bismarck National Weather Service.

This is a similar process to how storm survey teams look at tornado damage to then estimate the wind speeds associated with the tornado. It’s a process that also involves a bit of engineering knowledge to determine how severe the damage was.

“That’s where we actually look with the degrees of damage with certain things and even quantifies as a well-built structure or not so well-built. And that’s where we’ll range it a little bit,” said Schild.

After assessing the damage and based on atmospheric conditions that night, a tornado was ruled out in this case because debris from a tornado would be left in a circular manner compared to straight line wind damage that goes in the same direction.

“All the debris appears to have pushed to the east,” said Schild.

And as shown in this case, straight-line winds can be just as destructive as tornadoes.

“120 mile per hour wind gusts, that puts us in the scale of an EF-2 tornado, similar winds to that,” said Schild.

Storms of this magnitude are not very common in North Dakota.

Having a way to receive weather alerts, such as our weather call service, even during the overnight hours is important so that you can take shelter on the lowest floor and away from windows when severe weather strikes.

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