Romper la racha

[poli]

What does this mean?

[AngelicaDeAlquezar]

In this kind of expression, "racha" means a run of good or bad luck... It would mean to stop the run of bad luck here, as I assume no one would want to stop a run of good luck. :)

[chileno]

it means to break (the continuum) of good or bad luck as angelica explained.

[aleCcowaN]

It has a broader meaning. It implies breaking a consistent pattern of events. It refers automatically to luck -apparent patterns observed in a chain of events not causally related- in the set phrases "mala racha" and "buena racha", but it's used with any other pattern ("Fulania Club quebró una racha de diez derrotas seguidas como visitante") that has a partial component of chance.

[poli]

Thanks all. This is a good term to know.

[pierrre]

Crystal clear, aleCcowaN. I am going to make use of the expression now. Can it be used formally or only in informal contexts? I am thinking that an expression with 'rumbo' might be the formal one, but I am a West Indian who is willing to learn and use Spanish well.

[aleCcowaN]

Indeed, it's pretty colloquial --as everything related with patterns that can be abstracted from a background and seen as chance, luck, fate, fairy intervention, etc.-- but it can be used in pretty formal contexts to describe such patterns without hypothesizing about their causes or when the cause is known or obvious (a team full of good players is failing to achieve good team work and dynamics, so they're 'suffering' a "racha de diez derrotas consecutivas")

It's interesting to observe that racha means gust and it's used to describe winds that quickly change speed and direction. Particularly, those gusty winds that shake us constantly and quickly in a way we are uncomfortable keeping a standing position, they are called "vientos rachados" or "arrachados". So racha and the similar term ráfaga are used to describe the burst of a machine gun or a pattern of repeating events that suddenly starts and so disappears.

[AngelicaDeAlquezar]

[...]I am thinking that an expression with 'rumbo' might be the formal one[...]

"Rumbo" instead of "racha" doesn't make sense. "Racha", in the sense of luck, is indeed a colloquial expression, but not unsuitable in any context.
Perhaps one would prefer to say "Pedro necesita tener mejor suerte" instead of "Pedro necesita romper su mala racha", or "Tengo mucha suerte en el juego últimamente" instead of "Estoy teniendo una buena racha en el juego", but none would harm a formal context.