Nenana Ice Classic 2013

Posted: May 21, 2013 by tchannon in climate, Dataset, Natural Variation, weather


FAIRBANKS – The ice went out at 3:41 p.m. in Nenana on Monday and there was only one winning ticket holder in what was the latest breakup on record in the 97-year-old Nenana Ice Classic.

The official winning time was 2:41 p.m. Alaska Standard Time because the contest uses standard, not daylight, time to determine the winner(s).


The date and time was 2013, May, 20th, 2:41 PM AST, day 139.612 day 140.362  [correction]

The existing record 1964, May 20th, 11:21 AM AST, day 140.487   140.104  [correction], 1964 was a leap year.

This is a repost of an existing article with updates.


When I checked on the numeric data for the Nenana Classic I discovered NSIDC haven’t updated since 2003, NOAA don’t seem to provide in a simple format.

Ice Classic web site home page

Reference image



Whole articles are done quickly, not strictly, so lighten up if you want to complain about end corrected filters. Â Writing this before anyone…

I’ve added the later data to the old version, wrote a script and created a new version.

A tricky problem is the usage of 12:xx PM, meaningless. See this from NPL
I’ve assumed eg. 12:30 PM is 12:30 hrs

CSV in a .zip here (all of 2k) Updated to include 2013

Official data here, 2012 is missing.

[update]Â Gerhard Kramm at WUWT posts about the equinox suggesting 2013 is later in the year.

link here

Please discuss. Nothing like yet another confounding factor!



I thought I had corrected for the Gregorian calender wobble but on a detail check, no.

The effect does make 2013 the latest ice break date relative to earth orbit, without taking into account fine detail of orbital variation such as nutation.

This is now computed as julian day number modulo 365.24219 with the reference the nominal 1st Jan.

Data file has been updated.

If you think this is still in error, please say.

Post by Tim Channon

  1. Always worth remembering that the frozen river is down stream of Fairbanks, Alaska’s second largest city, with an urban population of 51,926. So it isn’t a crystal clear wilderness stream but one that is subject to urban influences. I have no idea how they keep the streets of Fairbanks ice free but any run off from that would be one small factor for instance…

  2. tchannon says:

    Can try this. Filter is end corrected, works okay.

    I wouldn’t be surprised if quite a few things are hidden variables.

  3. Douglas Proctor says:

    Weird how the to graph looks clearer for ten-day change in tilt day than bottom graph. Function of natural variability amplitude equal to delta gross change?

  4. In every open camera there is the possibility of one of these 30 second windows will reveal insights into the lives of the local population. This frame capture is right at moon rise!

  5. Berényi Péter says:

    An all time record is set.

  6. tchannon says:

    Nenana has gone.
    Very recent, no details.

  7. tchannon says:

    Article updated with new photo, plot including 2013 and updated data.

    The fun is going to be over the latest calender date but not the latest in the year, 1964 still holds that record. I suspect the Talkshop scoops this, not that many will be interested.

  8. Berényi Péter says:

    A true hockey stick, it is.

    BTW, weather could not care less about calendar dates, so the leap year meme is bs. What it does care about is the annual cycle of insolation. In 1964 the venereal (spring) equinox occurred at March 20, 5:10 AM AKST, in 2013 at 2:02 AKST.

    Therefore this year’s breakup happened 6 hours and 8 minutes later (61 days, 12 hours, 39 minutes in spring).

  9. Kon Dealer says:

    I guess this is just “weather”, unlike the tragic F5 Tornado in Moore, Oklahoma, which was “climate change”

    PS Climate Psience (TM) says: “The Ice Classic has given them a rare, reliable climate history that has documented to the minute the onset of the annual thaw as it shifted across 91 years. By this measure, spring comes to central Alaska 10 days earlier than in 1960, said geophysicist Martin Jeffries at the University of Alaska, Fairbanks — and that trend is accelerating. The Nenana Ice Classic is a pretty good proxy for climate change in the 20th century,” Dr. Jeffries said.

  10. philr1992 says:

    The calendar date/leap year hogwash is irrelevant…it’s the solar year (days past since the vernal equinox) that matters here (that’s where the physics of ice melt derive from). By that standard, the record is easily broken.

  11. tchannon says:

    Berényi Péter,
    The subject of fancy named orbital stuff I know nothing about, lots of words, no actual use to me.
    [that does not read well, not sure how to put it without sounding aggressive, not meant like that]

    So far as I am aware apart from a very slow time drift the orbit and calender relate well to each other. Any fixed reference will do, such as closest to the sun, about 4th Jan at the moment.

    The computation I have used was actually done to the Julian date, not Gregorian and this matches the figures of

    Dataset Originator/Creator: Nenana Ice Classic
    Dataset Title: Nenana Ice Classic: Tanana River Ice Annual Breakup Dates
    Dataset Release Place: Boulder, CO U.S.A.
    Dataset Publisher: National Snow and Ice Data Center (NSIDC)
    Online Resource:

    Has not been updated since 2003

    So as it stands I have no idea what is wrong, if anything. Perhaps my maths is wrong, perfectly possible, if so I want to correct.

  12. Berényi Péter says:

    @tchannon – There is nothing wrong with your math, the issue is with concepts.

    Our calendar is an arbitrary one, insolation is not. That’s what is the primary driver of climate, after all. Now, in 2013 there was a bit more insolation above Nenana (64.564° N, 149.093° W) at ToA (Top of Atmosphere) than in 1964, if we assume the solar constant is actually constant (which it is not).

    If the sun were steady, between March 1 & May 20 (in 81 days) there were about 4.2 MJ more incoming radiation in 2013 on each square meter above Nenana than in 1964. Of course, (a variable) part of that radiation was reflected back to space and even the fraction absorbed & thermalized either in the atmosphere or at the surface could be blown away by chilly winds. That’s weather.

    But, in spite of the primary forcing being larger, it took longer the ice to break up. That is, the spot over Nenana either rejected incoming energy more effectively this year than 49 years ago or it was more efficient in getting rid of the fraction already absorbed (or both).

    The additional energy this year, if fully absorbed, would be enough to melt a half an inch thick layer of ice. That’s not much, but something.

  13. tchannon says:

    I did make a mistake, rather silly, article and data has been corrected, which I hope is now good enough.

    Apologies to anyone inconvenienced or misled.