We are rapidly approaching the earliest known date (20 April) when the tripod on the Tanana River has crashed into the water. Anthropogenic Global Warming believers will be listening keenly for splashing sounds.
Ice thickness records at the Nenana Ice Classic over the years reveal that they are broadly significant, but not always vital for determining when the ice breaks up - there are many other factors at play, including rainfall, wind and river flow.
Latest ice measurements are here, which you can compare to previous years. Current ice thickness measurements are about the same as last year, when the tripod eventually crashed through on May 6.
The ice in 2008 and 2009 is thicker at the same stage than most recent years.
More commentary at the site. Good luck to all our brave guesstimators.