Temperatures in the Lower 48 have been way above normal again this year, but they’ve had nothing on Alaska. Heat records there continued to pile up through October as the notoriously chilly state heads towards its hottest year on record.

Through October, the year-to-date temperature in Alaska was 36.3°F, an astounding 6.7°F above average. This exceeds the previous record for the same period — set in 1926 — by 2.5°F.

Both November and December would have to be the coldest such months in the last 40 years for 2016 not to end as the hottest year on record for Alaska, according to climate scientist Brian Brettschneider.

The core of the October warmth was focused on western and northern Alaska. The west coast town of Nome saw its warmest October day ever recorded. The temperature soared to 59°F on Oct. 12, which was more than 20°F above normal for the date. Records there go back to 1906.

The Arctic Ocean coastal community of Barrow also had its warmest October day on record, reaching 44°F on Oct. 10. The normal high for the date is 25°F, and records there go back to 1920. In fact, every single day in Barrow had a daily average temperature above normal in October, leading to an average temperature for the month that was 12.9°F above normal. A new daily record high was set or tied six times during the month.

The Arctic is warming roughly twice as fast as the middle-latitudes and the tropics. That’s because if something is cold — like the Arctic — it takes less energy to raise its temperature compared to something that’s already warm. In other words, cold things are easier to warm than warm things.

The warm October has played a role in slowing the annual growth of Arctic sea ice, especially near the Alaskan coast. Some parts of the atmosphere over the Arctic Ocean had temperatures 14°F above normal during the month. Partly as a result, the average Arctic Sea ice extent for this past October was the lowest since satellites began monitoring in 1979.

arctic sea ice extent

Arctic sea ice extent as of Nov. 1, 2016, along with daily ice extent data for previous years. 

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The slowdown in the annual growth of Arctic sea ice feeds back on the Arctic temperatures. Ice is highly reflective and less of it means there’s more open water in the Arctic Ocean to absorb energy from the sun. As winter sets in, however, the sun will be below the horizon for several weeks in the Arctic. During that period, ice growth will become more dependent on the weather patterns until the sun rises again in early spring.

While Arctic sea ice grows every fall and winter, the amount of ice that survives the summer melt is decreasing, indicative of a long term warming trend. Old ice, in particular, is disappearing and leaving younger, more brittle ice in its place.

Even the ocean around Antarctica, which for a few years had a very high amount of ice, has had a very low amount of sea ice this year. Since Oct. 20, the daily sea ice extent there has been the second lowest in the satellite era. Only 1986 had a lower extent for this time of year.