“Along these lines I would argue that perhaps Matthew’s anomalous (severely under-predicted) intensification last week near the coast of South America was due to a tendency for that region to have low salinity” because of its proximity to the Orinoco and Amazon rivers, Elsner added.

“The circumstances surrounding Patricia were unusual, to say the least,” added MIT hurricane researcher Kerry Emanuel. “I agree with the authors of the study you are writing about that the unusual El Niño of 2015 played a role. But reduction of ocean mixing by extra salinity stratification, and higher than normal [sea surface temperatures] do not explain the whole problem.”

Emanuel said in his models, only when you also dial down an atmospheric parameter called “vertical wind shear” as well do you get a hurricane close to as strong as Patricia. Vertical wind shear refers to a situation in which winds in the upper and lower atmosphere blow in different directions, which can lead to the structure of a hurricane being blown apart.

The current study did not focus on the atmospheric conditions driving Patricia, noting that those would also have to be examined in the future.

“For this situation, it was record warm surface temperatures in the ocean, and a record deep pool of warm water,” said Foltz. “So it was just a really powerful combination of the two.”

October 12 at 12:12 PM