In 1998 there was one of the strongest El Nino events. https://en.wikipedia.org/wiki/1997%E2%80%9398_El_Ni%C3%B1o_event https://en.wikipedia.org/wiki/1997%E2%8

In 1998 there was one of the strongest El Nino events. https://en.wikipedia.org/wiki/1997%E2%80%9398_El_Ni%C3%B1o_event https://en.wikipedia.org/wiki/1997%E2%80%9398_El_Ni%C3%B1o_e... Maybe this made for a sudden increase, rather than a more gradual one.