Unusual Arctic Lightning Detected in 2019

The summer of 2019 saw an unprecedented amount of lightning in the Arctic region. This presentation will review 1) this unusual thunderstorm activity, 2) how it came to engage public attention, 3) the discovery of the northernmost lightning strike on record, and 4) the validation of the findings.

It is well known and observed that lightning is rare north of 70°N latitude, but some thunderstorms do occur there or develop at lower latitudes and then move northwards. On Saturday, August 10, NWS WFO Fairbanks, Alaska tweeted an image of a thunderstorm that had come within 300 miles of the North Pole. This generated significant interest in the media, with stories in the Washington Post, National Geographic, and Wired, among others.

As part of the investigation of the large August thunderstorm, Vaisala researchers looked back through our database to see whether there had been any lightning discharges that were even closer to the North Pole. While there were no storms found in previous years going back to 2012, there was a smaller thunderstorm on June 28, 2019 north of 88°N latitude. This storm included 19 strikes, including one at 16:40:33 UTC occurring less than 110 miles from the North Pole.

To ensure that this was signal and not noise, Vaisala engineers verified that these lightning strikes were in fact part of a thunderstorm, not an error in the data. Raw data from the sensors was analyzed and found consistent, with one strike detected by more than half the sensors in the global network. Further, the event was confirmed using 3rd-party data from JSAR Mapper showing cloud cover at the time of the thunderstorm.