Video S1: Time-lapse sequence of the break up of the ice melange, which took place from 11-17 April 2017 and occurred in pulses. The time-lapse rate is 1 s = 24 min. 

Video S2: Time-lapse sequence from 16-17 April 2017 showing the emergence of the plume at the fjord surface and ultimate dispersal of the ice melange. The time-lapse rate is 1 s = 24 min.