Eagle Lake Ice-Out

Summary

• Eagle Lake, in Bayfield County, is 163 acres with a maximum depth of 52 feet.
• Ice-out dates recorded from 1999-2000 to 2023-2024 ice seasons.
• Average ice-out date is Apr 17.
• Range of ice-out dates is approximately eight weeks from Mar 15 (in 2011-2012 and 2023-2024 ice seasons) to May 11 (in 2012-2013 ice season) (see Figure 1 and Figure 2).
• Ice-out dates have remained unchanged within the annual variability over this time period (see Figure 1).
• Ice-out dates were mostly similar to those from a nearby similarly-sized lake (see Figure 3).

 

Ice-Out Dates

Figure 1: Eagle Lake ice out dates (gray line and points) by year (note no data for 2008). Solid red line is a loess trend line.

 

Figure 2: Eagle Lake ice out dates, 1999-2023.

 

Comparison to Other Lakes

Lake Nebagamon is much larger (986 acres) but with a similar maximum depth (56 ft) as Eagle Lake that is approximately 20 miles nearly straight west of Eagle Lake. With the exception of a few notable years, the ice-out dates between these two lakes are quite similar. Lake Mendota is a very large (9781 acres) and deep (83 ft maximum) lake that is approximately 350 miles south of Eagle Lake. The ice-out dates for Mendota are always before those for Eagle Lake, but they very generally track together.

Figure 3: Eagle Lake ice out dates by year with other lakes shown for comparison.

 

Data Notes

These data were recorded by Gary Hagstrom. His general criterion was “complete ice out”; i.e., the lake completely devoid of ice with the exception of small remnants on north-facing shores.

Dates show above have been adjusted for leap years to maintain consistency across years. For example, Gary recorded ice out in 2024, a leap year, as 14-Mar but it appears as 15-Mar above to account for the extra “leap day” in Feb. In other words, 14-Mar is later in the year in a leap year then it is in a non leap year, which is accounted for above. Leap years are shown with triangles (rather than circles) in the time series graphs above.