The Pacific Ocean has set a new record for tropical storm and hurricane activity this year, driven by an exceptionally strong El Niño event and elevated ocean temperatures. Researchers at Colorado State University confirmed that the accumulated cyclone energy (ACE)—a measure of storm intensity and duration—has surpassed the previous seasonal record set in 2018.
Ocean temperatures in the central Pacific have reached unprecedented levels, according to Australia’s Bureau of Meteorology (BOM). Average weekly sea-surface temperatures in the region now exceed the previous record set during the 2015 El Niño event. Scientists note that these temperatures are occurring against a backdrop of long-term ocean warming due to climate change. For the first time, sea-surface temperatures above 30°C have been recorded in parts of the tropical Pacific, alongside record anomalies and exceptional subsurface warmth.
Record-Breaking Storm Activity
The Pacific hurricane season has produced an unusually high number of long-lasting and powerful storms. Since September 20, meteorologists have observed an extraordinary surge in storm activity east of the international date line, which affects regions including Hawaii, Mexico, and the U.S. West Coast. The ACE metric, which combines wind speed and storm longevity, has already surpassed the 2018 record, with additional storms expected to further extend the total.
Researchers attribute the heightened activity to multiple factors, including El Niño’s reduction of wind shear—a phenomenon that typically weakens storms. El Niño shifts high-altitude winds in a way that favors storm development in the Pacific while suppressing activity in the Atlantic. As a result, the Atlantic basin has experienced a record stretch without hurricanes, with the first forming on October 7.
Coastal Impacts in California
The heightened storm activity has already caused significant damage along the California coast. Researchers at Scripps Institution of Oceanography noted that parts of Southern California have experienced unprecedented coastal erosion and flooding ahead of winter storms. In Newport Beach, powerful waves breached protective berms, inundating roads with over a foot of seawater. The Wedge in Newport Beach, San Onofre, Laguna Beach, and San Clemente have seen substantial sand loss, altering shorelines.
Climate scientists emphasize that the current El Niño event is occurring in a context of long-term ocean warming, which amplifies the intensity of storms. The combination of natural variability and human-induced climate change has created conditions that are reshaping coastal landscapes and increasing vulnerability to extreme weather events.
Scientific Context and Measurements
El Niño is a naturally occurring climate pattern that typically recurs every two to seven years and lasts about a year. However, scientists are now using a Relative Ocean El Niño Index (RONI) to account for the additional warming caused by climate change. This adjustment allows for more accurate comparisons to historical events. Under this measure, the current El Niño’s intensity exceeds levels recorded during the 2015 event.
The BOM’s latest update highlights that the central Pacific’s sea-surface temperatures are now the highest on record, with temperatures above 30°C observed for the first time in the tropical Pacific. These conditions are contributing to the exceptional storm activity and coastal impacts observed this season.