Meteorology

There were several factors that came together to produce a wind event of this magnitude. As can be seen in the surface analysis loop below, there was a very tight pressure gradient (solid brown lines packed close together) that moved over western and central North Dakota behind a cold front, with low pressure to the east and high pressure to the west. 

Furthermore, a weather balloon launched near the Bismarck Airport around 5 AM CST on January 14 measured winds greater than 90 mph around 7,000 to 8,000 ft above the surface! 

While strong surface pressure gradients can produce strong winds on their own, another mechanism was needed for these winds to "mix down" to the surface. In this event, we had an unstable atmosphere with warmer temperatures at the surface than above (inferred by the negative slope of the red line). This type of temperature profile is very unusual for an early morning in January. Typically at this time of day and year, we observe what is called a temperature inversion, with colder temperatures at the surface than above (the red line would have a positive slope instead). If this had been the case, the atmosphere would have been stable, and the very strong winds aloft would have had a much more difficult time reaching the surface.