"Add frost on top of snow" (雪上加霜 xuě shàng jiā shuāng)

The common idiom first appeared in a Song Dynasty Buddhist text, Jingde Chuandeng Lu (景德传灯录) by Shi Daoyuan (释道原).

The original line:

It's like putting a head on top of a head — frost on top of snow."

犹是头上着头，雪上加霜。

It means two white disasters, layered on top of each other.

Like crops hit by snow, and then frost.

The same category of suffering compounded.

In modern Chinese, it's used whenever one misfortune compounds another.

For example, economic downturns hitting already-struggling industries, or bad news arriving at the worst possible moment.

Example:

Having your degree scrapped before you've even graduated, and then worrying employers will see you as damaged goods on top of that — that's like frost hitting after snowfall.

雪上加霜. 专业被撤销已经很难了，毕业后还担心被认为是"被淘汰的人"，真是雪上加霜。