Two La Niñas occurred two years after an El Niño, with a neutral year in between.
Notes on verification
Directly corroborated by verbatim NOAA ENSO blog statement, cited and matched by Smithsonian article.
Sources
- Say Goodbye to a Historic El Niño and Hello to La Niña (smithsonianmag.com)
- https://www.climate.gov/news-features/blogs/enso/may-2016-el-ni%C3%B1ola-ni%C3%B1a-update-switcheroo (climate.gov)
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5442129/ (ncbi.nlm.nih.gov)