August 13: This story has been updated with new data on the number of lightning discharges near the North Pole.
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 prompted 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 NWS stated. The lightning was detected using Vaisala’s Global Lightning Detection network, which has worldwide data going back to 2009. Other sources from NASA, for example, extend lightning information further back in time.
Reached by phone Monday morning, NWS Fairbanks meteorologist Ryan Metzger 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.
Well, that effectively confirms it. Satellite imagery clearly indicates deep convective clouds capable of producing lightning within 200-300 miles of North Pole along with --actual detected strikes--an extremely rare event. #PolarLightning #AKwx https://t.co/ql0P1QAiJY— Daniel Swain (@Weather_West) August 11, 2019
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.
Ryan Said, a research scientist for Vaisala who invented the GLD360 network to track lightning worldwide, put the lightning into historical context by searching through its data archives. According to him, between 2012 and 2018, the GLD360 network detected lightning north of 85 degrees just three times. “The maximum number of lightning discharges in any one storm event was 7,” he said. “We typically see 3 or 4 lightning storms north of 80 degrees each summer. We usually detect fewer than 50 discharges in each of these storms.”
There was one instance, on July 20, 2018, that the network caught over 300 lightning discharges north of 80 degrees, he noted.
However, the storms last weekend far exceeded the 2018 event. “For comparison, in the storm last weekend, we observed over three times that number (over 1,000 [discharges]) north of 80 degrees, with 48 discharges north of 85 degrees,” Said said via email.
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 broader context
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, Colo. Sea-ice extent is probably the lowest it has been in at least 1,500 years, based on recent research.