| Answer | Crossword Clue |
|---|---|
| ICEUP | Become unnavigable |
| ICEUP | Become unnavigable, perhaps |
| ICEUP | Become unnavigable in winter |
| ICEUP | Become unnavigable, as a sea in winter |
| SHOALY | Unnavigable, perhaps |
| URAL | Unnavigable river of Russia |
| ICINGOVER | Becoming unnavigable, in a way |
