FAIRBANKS - Record-thin ice on the Tanana River and unseasonably warm late winter weather could mean the earliest-ever toppling of the Nenana Ice Classic Tripod if the trend persists.
Measurements taken Sunday recorded ice thickness at 23.8 inches, significantly short of corresponding measurements taken in 1998, which is tied for the earliest river breakup on record.
On March 18, 1998, the ice was 43 inches thick, and the tripod tipped April 20. Ice thickness wasn't measured prior to 1989, but the ice also went out on April 20 in 1940.
"It very possibly could be a record year," Ice Classic manager Cherrie Forness said.
By comparison, the latest date ever for the ice to go out was May 20, in both 2013 and 1964. The March 18 thickness from 2013 was 50.3 inches.
The Nenana Ice Classic is a type of weather-based lottery popularized by railroad workers in 1917. People guess the exact date and time ice on the Tanana River will go out in the town of Nenana, with prize pools often in the hundreds of thousands of dollars.
Tickets are on sale until April 5, and Forness said she expects the ice will hold long enough for the organization to keep that date. However, if conditions rapidly deteriorate, organizers may close ticket sales sooner.
"I don't think it we will before the fifth. I think it will hang on until then, but who knows what after that," she said.
According to Forness, volunteers will begin taking ice measurements twice per week until it's unsafe to go out on the ice. Biweekly measurements are normally reserved for April but were advanced this year because of the thin ice.
The Nenana Ice Classic webcam shows pools of water surrounding the tripod, but Forness explained it's from snowmelt, not river ice.
She expects the water pools will continue to melt in the day and refreeze at night until temperatures stay above freezing. A lot of factors contribute to breakup on the Tanana River, such as breakup downstream on the Nenana River and the movement of ice upriver on the Tanana.
The Nenana River is starting to show open pockets of water, Forness said.
"We need it to open up upriver from us as well. There's gotta be ice moving down the river to help move out the ice in Nenana, and it needs to go somewhere," she said.
Forness noted that she plays the Ice Classic every year and that her guess this year will reflect the thin ice. "I'm going early. I don't know how early, but I'm definitely going to go early," she said.
Contact staff writer Robin Wood at 459-7510. Follow him on Twitter: @FDNMcity.