RORY: That was just my mom being funny.
LORELAI: Yeah, it comes and goes. You’ll learn to notice the signs.
CHRISTOPHER: The waves get really still, the animals start to act funny.
Christopher humorously compares Lorelai’s sense of humour to natural disasters, as if it is a force of nature. The waves of the sea become calm just before a storm hits, while animals are said to act strangely before an earthquake.