Time series of open water area in the greater PIP area for the months of November to March starting in 1978 for November and December, and in 1979 for January to March (and ending in 2012 and 2013, respectively). The linear trends for January (523 ± 318 km² yr⁻¹, p < 0.01) and February (551 ± 353 km² yr⁻¹, p < 0.1) are shown for reference (while trends in other months were not significant at the p < 0.1 level). Note that there was only one year when November showed a small open water area (the small blip in 2001 corresponding to 641 km²).