The midnight sun shines across sea ice along the Northwest Passage in the Canadian Arctic Archipelago, July 23, 2017. Credit: David Goldman | AP

On Saturday, multiple lightning strikes were detected within 300 miles of the North Pole, according to the National Weather Service. The bolts, which were the product of towering storm clouds that, if seen in lower latitudes, would amount to ordinary thunderstorms, were noticed by sharp-eyed forecasters at the weather service office in Fairbanks, Alaska.

The thunderstorms at the top of the world struck in the midst of an extreme summer that has featured record-low sea ice levels and much-above-average temperatures across much of the Arctic Ocean, including at the pole itself. In Greenland in late July and early August, an extreme weather event led to record levels of ice melt into the sea, tangibly raising global sea levels. A wildfire has been burning in western Greenland for more than a month, illustrating the unusually dry and warm conditions there.

The polar lightning was so rare that it led the weather service to issue a public information statement late Saturday, which said in part: “A number of lightning strikes were recorded between 4 p.m. and 6 p.m. today within 300 miles of the North Pole.” According to the statement, the strikes hit the surface, which was probably made up of sea ice or areas of open ocean waters mixed with ice, near 85 degrees North, 120 degrees East. “This is about 700 miles north of the Lena River Delta in Siberia.”

“This is one of the furthest north lightning strikes in Alaska forecaster memory,” the weather service stated.

Reached by phone Monday morning, meteorologist Ryan Metzger at the weather service’s Fairbanks office hesitated to say that lightning so close to the pole has never been seen before, in part, because forecasters aren’t always looking there. “I wouldn’t say it’s never happened before, but it’s certainly unusual, and it piqued our attention,” Metzger said.

He said he’s confident that the strikes were not errors in the lightning detection network, which spans the globe, because they tracked along with the clouds’ movements.

The lightning strikes mean that the atmosphere near the pole was unstable enough, with sufficient warm and moist air in the lower atmosphere, to give rise to thunderstorms. The loss of sea ice across the Arctic has led to sea surface temperatures that are much above average for this time of year, which may be contributing to unusually unstable air masses being pushed across the central Arctic Ocean.

The vast majority of Earth’s thunderstorms occur at lower latitudes, where the combination of higher temperatures and humidity more easily sparks such weather phenomena. However, as Alaska and other parts of the Arctic have warmed in response to human-caused global climate change, there is evidence that thunderstorms are starting earlier in the year and are extending to areas that didn’t used to see many such events, such as Alaska’s North Slope.

One reason to be cautious about interpreting the lightning as an unprecedented event is that lightning can also occur in intense nontropical storms that affect the Arctic, though no such large and potent storm was present Saturday. This does make the weekend lightning stand out, however.

The Arctic climate has seemingly gone off the rails this summer. There is no longer any sea ice present in Alaskan waters, with Bering Sea ice having melted out beginning in February, and ice in the Chukchi Sea already pulling back hundreds of miles north of the state. Alaska had its hottest month on record in July. Wildfires are burning across the state, and fires in Siberia have sent plumes of dark smoke into the Arctic, where soot particles can land on the ice and snow and speed up melting.

In July alone, the Greenland ice sheet poured 197 billion tons of water into the North Atlantic, which was enough to raise sea levels by 0.5 millimeter, or 0.02 inches, in a one-month time frame. On Aug. 1, Greenland had its biggest single-day melt event on record, with 12.5 billion tons of surface ice lost to the sea.

Across the Arctic, sea ice is at record to near-record low levels for this time of year and is likely to end the melt season with one of the five lowest ice extents on record in the satellite era, according to the National Snow and Ice Data Center in Boulder, Colorado. Sea-ice extent is probably the lowest it has been in at least 1,500 years, based on recent research.