Agencies: Alaska, the coldest state in the United States, recorded its warmest days ever in December, amid an unusually warm winter period.

Temperatures rose to a record level of 19.4 degrees Celsius on Kodiak Island on Sunday, nearly seven degrees warmer than its previous highest levels in the state.

But temperatures have dropped to record levels in other parts of Alaska.

In the southeastern town of Ketchikan, temperatures dropped to 18 degrees below zero on December 25, one of the coldest Christmas days in the city in the past century.

Weather fluctuations have prompted warnings from authorities, while floods from rain and snow left hard ice on the cement covering the roads.

Experts say that the warm air flowing from Hawaii made Alaska’s air, which is usually cold and dry during December, more humid. This means heavy rainfall and snowstorms are more likely in the interior, away from the mild coastal areas.

The heavy snowfall was followed by heavy rain that left the area covered in ice as the rain froze quickly, causing widespread power outages and road and office closures.

The Alaska Department of Transportation and Public Facilities warned of thick ice formation on the roads, which deceives drivers.

The department said on Twitter, "It is extremely difficult to remove ice once it sticks to the road surface. Although temperatures were warm ... the roads were below freezing temperatures, causing the ice to stick to the surface."

Climate scientist Rick Thoman, from the Alaska Center for Climate Assessment and Policy, told the BBC that the ice is likely to cling to the roads until March or April at least.

Thoman explained that the fiercest mid-winter storm since 1937 hit the city of Fairbanks in the central part of the country during Christmas, causing over 10 inches of snow to fall.

Heavy snowfall occurred on Sunday, causing the roof of the only grocery store in the town of Delta Junction, 153 kilometers southeast of Fairbanks, to collapse.

Thoman said that sharp shifts in temperatures from extreme cold to warm over the past two decades have been a sign of climate change.

The cold is expected to return, with temperatures in Fairbanks expected to drop below 29 degrees Celsius below zero by the end of this week.

But Thoman expects warm, rainy periods to become more frequent in the future.

He told the BBC, "It seems that 2021 really is the year when severe rainfall emerged prominently."