ADJ-GRADED （问题或坏事）不可预见的，难以预测的 An unforeseeable problem or unpleasant event is one which you did not expect and could not have predicted. （问题或坏事）不可预见的，难以预测的
...severe unforeseeable weather conditions.
不可预测的恶劣天气
This is such an unforeseeable situation that anything could happen.