Breakup, freeze-up, and open water in the community areas for 1996–2016. The timing of open water conditions (ice concentration < 20%) for 1996–2016 in the four community areas. Black data depict the week of the year for breakup and freeze-up; blue data depict the number of weeks in the open water season. Green squares around data points indicate that there was a continuous channel of open water from the community area to the eastern edge of the study area at the time of breakup or freeze-up. Red lines show the average value for each 1996–2016 time series. DOI: https://doi.org/10.1525/elementa.281.f8