Ice Out


Thanks to Melissa Ostlie we are starting a data base on “Ice Out” dates. If any other members have data to add to this data base please send to me.

2006 was april 12
2007 was april 21
2008 was may 4th
2009 was april 24

2010 was april 1st

Minnesota’s Historical Lake Ice-Out Dates

The definition of lake ice-out varies from lake to lake, and individual to individual. For some, ice-out occurs only when the lake is completely free of ice. For others, ice-out is defined as the moment when navigation is possible from point A to point B. And yet for o

thers, ice-out is when 90 percent of the lake is ice free. Due to the variable definitions of this rather subjective observation, the State Climatology Office attempts to contact the same individuals each year to maintain a consistent record. The table below summarizes historical lake ice-out averages and extremes for Minnesota lakes with 10 or more years of record.
In addition to differences in ice-out observation techniques, the variable period of record and variable length of record makes lake to lake comparisons of averages and extremes problematic. Differences in lake size, lake depth, and lake geometry also generate a large amount of variability among lakes in close proximity. In spite of these inherent problems, the tables below demonstrate a recognizable pattern in average lake ice-out across Minnesota, and also call attention to years of very early or very late lake ice-out.

For comparisons below are a couple of area lakes with their data.

Lake Average Earliest Latest Years
Ice out Ice Out Ice Out of Data

Detroit April 19th March 23, May 19, 111
1910 1908

Sallie April 18th April 3, May 7, 27
2000 1979