unnavigable

adj.不可通航的

不可航行的；不可通过的

形容词

1. The river was so swollen and rapid that it became unnavigable for small boats.
这条河水涨得很快，流速很快，小船已经无法航行。

2. Heavy snowfall made the mountain roads unnavigable, causing transportation difficulties.
大雪导致山区道路不可通行，给交通带来了困难。