Under more traditional circumstances, avid gamblers and climate scientists would seem to make for strange bedfellows. Yet Alaska's Nenana Classic, a yearly contest to guess the amount of melted ice on the River Tanana, has steadily built a cult following over the past few decades - attracting equal numbers of betters and world-renowned climatologists (the $300,000 prize tag certainly didn't hurt). As The Sunday Times' Tony Allen-Mills explains, the contest has (perhaps surprisingly) become one of the world's most accurate indicators of the impact of global warming. This tradition of timing the first cracks in Tanana's ice dates back to over nine decades; before it even attracted legions of enthusiasts, the melting was already being meticulously recorded by the small village's 500 residents.
This year, the Nenana Ice Classic will attract tens of thousands of Alaskans and a large number of foreigners; betting will close at midnight on April 5. The contest's organizers have been monitoring the Tanana's ice cover twice a week since mid-March: at last count, the ice was 44.5 in thick. Scientists eager to obtain more data and gamblers will now wait for the moment a 26 ft wooden tripod, mounted on ice with a siren and clock in the middle of the Tanana, falls over to signal the ice breaking off.