The first three weeks of August the average temperature in Fargo was nearly 4 degrees below average. One of the principle reasons for that change in the weather pattern was the development of a massive Arctic cyclone during the first week of August. That storm at peak intensity had a lower atmospheric pressure reading than Hurricane Isaac did.
It pushed the cooler Arctic air south into North America and in turn, warmer air from the Atlantic Ocean into the Arctic. The combination of the very strong wind and warmer air from this system caused a massive break up of Arctic ice. During a three day stretch nearly 250,000 square miles of ice was ripped off the ice pack and in turn melted. Of course, additional ice was also broken up by the storm that lasted nearly a week.
That storm in combination with another above normal ice melt pushed the Arctic ice pack to its lowest level since 1979 according to the National Snow and Ice Data Center.