This week, freezing temperatures and lots of snow wreacked havoc across Europe, stranding many holiday travelers. But on the other side of the Atlantic, some equally unusual weather has kept parts of Hudson Bay from freezing over, causing the growth in Arctic sea ice to come to a halt. To find out whether these two events might be related, we talked to Mark Serreze, head of the National Snow and Ice Data Center.

The two weather events are linked by a mass of unusually high pressure air that is sitting over central Greenland, Serreze said. A cyclonic rotation has formed around that high pressure area, and the southward rotation pulls air out of the Arctic and sends it heading towards Europe. Hence, the freezing temperatures.

On the other side of Greenland, the rotation is pulling warmer air out of the south—the normally frigid Baffin Island is experiencing temperatures above freezing, a rarity in December. This has left large areas of Hudson Bay and the Davis Strait, which are normally frozen over, with limited areas of sea ice. The end result is that the trajectory of sea ice growth has taken a sudden dip.

It's very interesting," Serreze said. "It's essentially been flat, maybe it's gone down a little bit." He made it clear that this had been seen before, so it wasn't unprecedented to have a December pause. He also noted that this wasn't an instrument error; although the NSIDC relies on a satellite sensor called SSM/I, other satellites are seeing the same thing. Nevertheless, the change has left us with the lowest ice levels at this date since they've been recorded by satellite.

Serreze said that, in the global sense, this situation is similar to the strong North Atlantic Oscillation event that brought cold temperatures to Europe last winter. And this sort of local weather event mostly redistributes the air, so it doesn't have a huge impact on global temperatures. Europe had already started to cool off in November, and that turned out to be the warmest November on the instrument record.

But Serreze pointed out two ways that the current weather might be connected with long-term trends in the Arctic. The intense high pressure over Greenland is associated with a strong low pressure area a bit northeast of Iceland. That will tend to pull ice out of the Arctic, and may contribute to the ongoing decline of thicker, multi-year ice. The thinner ice that's replacing it is more prone to melting rapidly in the summer.

There's also a chance that the loss of sea ice is feeding back into the system. Serreze said that the research community was beginning to suspect that the lack of sea ice allows the oceans to pump heat into the atmosphere in the Arctic in a way that could impact local weather, including the North Atlantic Oscillation. He described the idea as "very much in its infancy," but said that it's something the community was looking into seriously. If it turns out to be right, the frigid winters Europe has experienced these past two years might become the norm.