People who want to participate in Alaska's biggest guessing contest have until Sunday to buy tickets for the Nenana Ice Classic. Thousands of people each year pay to try to guess the exact date and time the ice will break up on the Tanana River in Nenana. Each guess costs a $2.50 ticket. The most recent ice thickness measured about 35 inches, according to the Fairbanks Daily News-Miner.
Each year, a clock is connected by cable to a wooden tripod anchored in the river ice about 300 feet from shore. When the ice breaks up and the tripod falls or moves, the cable tightens and stops the clock. The ice went out last year at 3:48pm on April 25. The record winning pot totaled $363,627 and was split among 25 tickets. (Read more Alaska stories.)