freeze-up

noun

plural -s

: a freezing over of a body of water especially when marking the onset of winter

goes on duty in April, just before the swans arrive, and stays with them until they leave at freeze-up

Lyn Harrington

: a period during which the bodies of water in an area are frozen over

the freeze-up lasted six weeks last year

before the freeze-up sets in

V. E. Fuchs

all their food for seven months had to be taken to camp before the winter freeze-up

Bill Wolf