snowballing

noun

1. (countable, uncountable)The act or practice of making and throwing snowballs.
2. (countable, figuratively, uncountable)A situation which rapidly gets out of control.

verb

1. (form-of, gerund, participle, present)present participle and gerund of snowball

   “"Operating the WCML at this intensity makes it challenging to maintain acceptable performance levels, resulting in a frustratingly unreliable service for passengers. Minor disruption can escalate into significant delays because a train running only a few minutes late can miss its slot across a junction, resulting in a snowballing effect across the network."”