形容詞 ice-free:

1. free of ice and open to travel

ice-free

adj.（形容詞）
Free of ice and open to travel or navigation:
不凍的：不結(jié)冰的并可向旅游或航行開放的：
例句：
an ice-free channel in the river.
河流中不結(jié)冰的水道

Marked by a lack of obstructive ice:
無冰的：以沒有阻礙性冰為特征的：
例句：
a three-month ice-free period during the summer.
夏季三個月的無冰期