by S.J. Crockford, July29, 2019 in ClimateChangeDispatch
In late June, one of the most powerful icebreakers in the world encountered such extraordinarily thick ice on-route to the North Pole (with a polar bear specialist and deep-pocketed, Attenborough-class tourists onboard) that it took a day and a half longer than expected to get there.
A few weeks later, in mid-July, a Norwegian icebreaker also bound for the North Pole (with scientific researchers onboard) was forced to turn back north of Svalbard when it unexpectedly encountered impenetrable pack ice.
Apparently, the ice charts the Norwegian captain consulted showed ‘first-year ice‘ – ice that formed the previous fall, defined as less than 2 m thick (6.6 ft) – which is often much broken up by early summer.
However, what he and his Russian colleague came up against was consolidated first-year pack ice up to 3 m thick (about 10 ft). Such thick first-year ice was not just unexpected but by definition, should have been impossible.
Ice charts for the last few years that estimate actual ice thickness (rather than age) show ice >2 m thick east and/or just north of Svalbard and around the North Pole are not unusual at this time of year.
This suggests that the propensity of navigational charts to use ice ‘age’ (e.g. first-year vs. multi-year) to describe ice conditions could explain the Norwegian captain getting caught off-guard by exceptionally thick first-year ice.