The GI-31 ice history is constructed based on the ICE-6G ice history (Peltier et al., 2015, doi:10.1002/2014JB011176). We construct an alternate ice model (GI-31) by modifying the deglaciation geometry of the ICE-6G model while requiring that the total ice volume (or global mean sea level) history of that model be preserved in order to satisfy far-field sea-level constraints. We delay ice loss in the CIS/western LIS region within the zone west of 110°W, preserving the ICE-6G ice distribution at 15 ka in this specific region until 13 ka. The ice distribution from 15-13 ka is modified to be consistent with the median ages reported in a large dataset (n= 818) constraining the deglaciation chronology of this region. In particular, we require that regions with minimum ages older than 13 ka must be ice-free by 13 ka in the GI-31 ice history. Peltier, W.R., Argus, D.F. and Drummond, R. (2015, doi:10.1002/2014JB011176). Available here: http://www.atmosp.physics.utoronto.ca/~peltier/data.php

Supplement to: Pico, Tamara; Robel, Alexander; Powell, Evelyn; Mix, Alan C; Mitrovica, Jerry X (2019): Leveraging the Rapid Retreat of the Amundsen Gulf Ice Stream 13,000 Years Ago to Reveal Insight Into North American Deglaciation. Geophysical Research Letters, 46(21), 12101-12107