Southern Mexico’s Pacific coast was braced for a Thursday morning impact with the approach of Hurricane Erick, which was upgraded to an “extremely dangerous” Category 4 early Thursday, the U.S. National Hurricane Center said.

Forming in October, Otis grew stronger by churning up deeper and warmer water because it was later in the year. Erick is early in the year and the deep water it would churn up is cooler and doesn’t fuel rapid intensification. Even so, the surface water is plenty hot enough, said MIT hurricane scientist Kerry Emanuel.