Friday, April 26, 2024

Official Ice Out Date with statistic analysis

Spotters reported that all of the sheets of ice were gone from the lake on April 8th. That date was our date of ice out on Long Lake and reported to the DNR. 

Ben Cachiaras guessed the exact date this year. At the Annual Meeting (June 29th), we will draw from the 44 entries for the grand prize.  Last year ice out was May 3rd. In 2000, 2016 and 2017 ice out was around this date.

The following are the charts for Long Lake Ice Out as calculated by Vern Campbell.  The average date is April 20, so 2024 was about 12 days earlier than the average.  The charts indicate that although the Ice Out this year was slightly earlier than average, it is still within the bounds of normal random variation.  Just as a reminder, the UCL = May 22 and the LCL = March 19 are calculated values and are +/- 3 standard deviations from the mean date of April 20.  Therefore, basically if dates are normally distributed and fall between May 22 and March 19, then we can basically conclude that any deviation we see from the average is simply normal random variation.  Thus far, the Ice Out dates indicate random variation about the average ice Out date of April 20. 

(On the graph below, UCL = Upper Control Limit: LCL=Lower Control Limit)