Alaska sets record high December temperature of 19.4C

An unusual winter warm spell in Alaska has brought daytime temperatures soaring past 15.5C (60F) and torrents of rain at a time of year normally associated with bitter cold and snow.

The most serious immediate implication for humans is likely from the massive amounts of precipitation dumped on interior Alaska, where the Fairbanks area was hit by its fiercest mid-winter storm since 1937, Thoman said.

But so much snow fell that on Sunday it caved in the roof of the sole grocery store in Delta Junction, a town 95 miles (153km) south-east of Fairbanks.

Possibly worse, the heavy snows were followed by torrents of rain that coated communities in the region with ice, triggering widespread power outages and prompting closures of major roads and offices, as well as a nickname: Icemageddon.

The Alaska Department for Transportation warned that roads will remain treacherous for a long time because of the cement-like ice coating that has formed on them.

The story is similar elsewhere in the far north, where winter rains have proved treacherous to people and to grazing animals, like caribou and musk oxen, that struggle when ice on the ground covers food sources. Such hardships are expected to intensify.

A study published last month in the journal Nature Communications projected an Arctic climate with more winter rain than snow starting around 2060 or 2070.