Tanana River
Nenana, Alaska

Ice-out Contest

About This Site
The Tanana River (65.5N, 149.0W) is at the Nenana, Alaska Ice-Out Observation Post. Since 1917, spring's official arrival in this Interior Alaskan town is defined as the moment the Tanana River is ice free. This event is measured down to the second with a tripod erected on the ice with a trigger to an official clock.

To help in your prediction, see the Tanana's ice-out dates since 1990:

Year

Month

Time

1990 April 24
5:19 p.m.
1991 May 1
12:04 a.m.
1992 May 14
6:26 a.m.
1993 April 23
1:01 p.m.
1994 April 29
11:01 p.m.
1995 April 26
1:22 p.m.
1996 May 5
12:32 p.m.
1997 April 30
10:28 a.m.
1998 April 20
4:54 p.m
1999 April 29
9:47 p.m.
2000 May 1
10:47 a.m.
2001 May 8
1:00 p.m.
2002 May 7
9:27 p.m.
2003 April 29
6:22 p.m.
2004 April 24
2:16 p.m.
2005 April 28
12:01 p.m.
2006 May 2 5:29 p.m.
2007 April 27
3:47 p.m.
2008 May 6
10:53 p.m.
2009 May 1
8:41 p.m.
2010 April 29  
2011 May 4  
2012 May 1  
2013 May 20  
2014 April 25 3:48 p.m.
2015 Your guess?  


Tanana River

Tripod on the Tanana River in Nenana, Alaska

 

The Tripod Story
Each year a black-and-white tripod is "planted" into the ice of the Tanana River. A wire attached to a rope runs from the top of the tripod to a contraption in a watchman's tower on shore. Watchmen make sure nobody messes with the tripod. Anticipation builds as the weather warms. The ice under the tripod gets slushy, and then the water begins to flow. When water flows on the bank near the watchtower, the time is near. One day or night, the rocks jerk to the top of the tower as the tripod begins its journey, jerking along as the breaking ice chunks begin to move! One watchman described it as just like an earthquake, with rumbling and shaking when the ice starts to go.

When the ice breaks and the tripod begins to move, the rope raises a 50-gallon drum of rocks to the top of the tower. The action trips another line that releases a guillotine that cuts the main rope to the tripod. The cutting of that rope trips two other ropes. One rope stops a clock and the other sets off a loud siren. That's when the whole town finds out the winner of Alaska's oldest lottery, the Nenana Ice Classic. It's a big deal because the Ice Classic has handed out millions of dollars in prize money since 1917--for guessing the exact time the ice breaks up. What's YOUR guess for this year?