The weather was stormy. The fishermen had been warned the previous night. The fishermen were in danger. Anyone could have got drowned in such weather.
1:
The weather was so stormy that anyone could have got drowned and the fishermen were in danger, so they had been warned the previous night.
2:
The weather was stormy enough to have the fishermen in danger as they had been warned the previous night and anyone could have got drowned in such weather.
3:
The fishermen had been warned the previous night as they were in danger in the weather was stormy and anyone could have got drowned in such weather.
4:
The fishermen were in danger as the weather was stormy as they had been waned the previous night and anyone could have got drowned in such weather.