Lake Ice and 
Snow Science 
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WHY STUDY LAKE ICE AND SNOW?

Changes in Freshwater Ice

There is ample evidence that freshwater ice freeze-up, break-up and ice duration (referred to as phenology) are primarily a function of weather and climate, particularly air temperature.

The Magnuson et al. (2000) Northern Hemisphere data (right) show a trend towards:

  • later freeze-up,
  • earlier break-up and
  • shorter ice duration (decrease of 20 days since 1845)

This equals a temperature change of 1.2°C per 100 years.

Summary graph of changes in river and lake freeze up an break up in the northern hemisphere
Note: break up dates trend downwards (earlier), freeze up dates trend upwards (later) and duration values trend downwards (shorter).

Source: Magnuson et al. (2000) and NSIDC.

Nenana Ice Classice data compared with Arctic Temperature data

The Nenana Ice Classic data documents the first movement of ice on the Tanana River. As of spring 2004, break-up was occurring 5.2 days earlier relative to the vernal equinox than in 1917. The advance of break-up is strongly related to rising spring mean air temperatures.

More information: Nenana Ice Classic data.