DCHP-1 Online
break-up period 
the period of time taken for the ice in rivers and lakes to soften, crack up, and disappear.
See also: break-up (def. 3) ice-out season melt season open water (def. 2)
- 1956 It was at Stanley, during a break-up period when we encountered a particularly vicious bush-fire.
- 1958 The small payload capacity, frequent weather delays and the stagnation of all float or ski-equipped planes during the break-up and freeze-up periods in the north contributed to the high cost and relative inefficiency of bush plane transport.
- 1956 It was at Stanley, during a break-up period when we encountered a particularly vicious bush-fire.