The science behind strong winds in North Dakota

Published: Nov. 26, 2021 at 8:22 PM CST
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BISMARCK, N.D. (KFYR) - North Dakota is certainly no stranger to strong winds, but you may have noticed an increase in the amount of windy days within the past few weeks. There’s a reason for this, as we typically see more strong winds in the fall.

It all starts when an area of high pressure and low pressure are close by, with winds flowing from the area of high pressure to the area of low pressure. Between these two pressure centers, a strong pressure gradient can develop leading to strong winds at the surface.

“The winds a couple thousand feet above the ground or more are typically higher than the winds you see at the surface, and that’s because there’s less friction the higher you go up in the atmosphere compared to at the surface. Under certain conditions the atmosphere will become unstable, which just means that air at the surface can more easily move up into the atmosphere and air at higher levels can more easily move down,” said Brandon Gale, meteorologist with the National Weather Service Bismarck.

With temperatures at the ground warmer than higher up in the atmosphere, this can allow the stronger winds to mix down to ground level.

Strong winds aloft (where it's cooler) can mix down to the surface (where it's warmer) under...
Strong winds aloft (where it's cooler) can mix down to the surface (where it's warmer) under certain circumstances (KFYR)

And even though strong winds can be seen year round in North Dakota, the transition seasons of spring and fall generally have more long lasting and high-end strong wind events.

During the summer the jet stream is typically farther to the north and slower moving, but that changes during the fall.

Jet stream pattern in the summer
Jet stream pattern in the summer(KFYR)

“In the spring and fall months the difference between the warm area and the cold area is stronger, which makes the jet stream stronger as well. And the jet stream is higher up in the atmosphere, and when we get those winds to mix down to the surface we get those strong wind gusts that are being influenced by the temperature and the pressure,” said Gale.

Jet stream pattern in the fall
Jet stream pattern in the fall(KFYR)

But at what level do winds become dangerous?

“Generally when the winds approach 30 miles per hour that’s when it can start getting a little bit dangerous for the high-profile vehicles, especially if there’s a cross-wind. But once we get closer to 60 miles per hour that’s when you can start to see damage on trees and buildings and other objects that are outdoors,” said Gale.

Damaging wind categories (the Beaufort Scale)
Damaging wind categories (the Beaufort Scale)(KFYR)

And we saw some of the damage that these strong winds can create about a week ago when 60 to 70 mile per hour wind gusts were reported across the region. And with a La Niña pattern in place this fall and winter, that’s favorable for Alberta clippers to move through our region, possibly bringing us some more strong wind events.

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