The Global Lake and River Ice Phenology Database contains freeze and
breakup dates and other ice cover descriptive data for 748 lakes and
rivers. Of the 429 water bodies that have records longer than 19
years, 287 are in North America and 141 are in Eurasia; 170 have
records longer than 50 years; and 28 longer than 100 years. A few have
data prior to 1845. These data, from water bodies distributed throughout the Northern Hemisphere,
allow analysis of broad spatial patterns as well as long-term temporal patterns.