上周的霜冻对柑橘种植业是一场大灾难.The frost last week was a great calamity to the citrus industry.洪水是一场大灾难.The flood was a major catastrophe.小错误可能会招致大灾难。A slight mistake could precipitate a disaster....

“大灾难”的英语可以翻译为：catastrophe ...