That when things get bad, it will only get worse.
The cast of When it Rains it Pours - 2005 includes: Nick Stevenson as Warren
Pours
The phrase "when it rains, it pours" is a metaphor for how when one bad thing happens, several more seem to follow in quick succession. It highlights the idea that challenges or difficulties often come all at once rather than being spaced out.
A counterexample for "when it rains it pours" could be a situation where it rains lightly throughout the day without escalating into a heavy downpour. This would go against the idea that once it starts raining, it will intensify significantly.
When it rains it pours!
"And just like that, we're all in fright"?
Big Break Dominican Republic - 2010 When It Rains It Pours was released on: USA: 2010
Farm Kings - 2012 When It Rains It Pours 1-5 was released on: USA: 25 October 2012
It tends to get really frizzy.
Morton Salt's motto is 'When it rains, it pours.'.
While I've never specifically heard it phrased precisely like that before, it's conceptually similar to the cliche "it never rains but it pours."