Hi Amin, This idiom refers to a particularly bad situation, with an emphasis on the fact that the bad situation is caused by the combination of several negative factors which led up to this "perfect storm". Example: An unusual heat wave and lack of firefighting services in an area are negative factors. Should a bush fire start, the nearby town will have to brace itself for a perfect storm. The idiom can also be used to mean what the individual words describe: A Perfect Storm. A violent storm that is the effect of several unfavourable meteorological factors. Hope this helps. Cheers, Lance