US freeze too cold for polar bears
All 50 states recorded temperatures below zero
ALL 50 of America's states recorded temperatures below freezing. It was so cold even the polar bear at Chicago Zoo spent most of the day indoors.
Parts of the country not victims of the "polar vortex" that afflicted swathes of the US suffered abnormally chilly weather as the authorities declared it the coldest January 7 on record.
The lowest temperature was reported at Embarrass, Minnesota, a township of just over 600 people, where the thermometer fell to -37C. Once the wind chill was taken into account, the temperature felt as low as -43C.
On Hawaii, the weather station on Mauna Kea, the island's highest mountain, recorded -6C and temperatures plummeted at all levels in the southern states of the US mainland.
In Chicago, the zoo's polar bear, Anana, which has less insulating fat than if it lived in the wild, was kept in its heated indoor enclosure all day on Monday and ventured outside only briefly yesterday as the thermometer fell to -27C.
At least 15 people are believed to have died across the US as a result of the cold blast, which has crippled much of the country. According to the latest figures, 187 million people have been affected by the severe weather.
Across the country, wind chill warnings were in place for 32 states from Montana in the north to Florida in the south east.
School closures were reported from as far afield as Minneapolis and Chicago in the north to Atlanta and northern Florida in the south.
The eastern seaboard, which had escaped the initial impact of the polar vortex, was also affected. Andrew Cuomo, the governor of New York state, closed swathes of the state highways as a precaution.
It was so cold that water thrown into the air turned into ice before landing on the ground.
In Iowa, Tom Rauen became an internet sensation when he posted a film on YouTube showing a wet T-shirt turning into ice in a minute.
"I thought it would be cool if I could shape it into what it would look like if someone was wearing it," he said.
"I left it standing up on the sidewalk for a while and when I brought it inside there was a little tear in it -- just from it freezing, it had become it very brittle. I took the tear and just ripped the T-shirt in half like it was a piece of paper. It was crazy."
The cold weather in the south triggered fears that the Florida citrus crop could be hit. America's transport system continued to be affected.
In Illinois, more than 500 passengers were stuck on three Amtrak trains overnight after they were trapped by the snow. Thousands of flights were cancelled across the country.
Temperatures are expected to climb slowly by the end of the week. (© Daily Telegraph, London)