June-December North PAcific ACE vs. June-December ENSO Intensity, 1980-2014. This graph shows the relationship between El Niño, La Niña and ENSO neutral years and the Pacific Ocean ACE Index. Graphic: Philip Klotzbach

By Andrew Freedman and Johnny Simon
23 October 2015 (Mashable) – UPDATED 2:45 p.m. ET: Since this story was posted, yet another storm — Hurricane Patricia — in the eastern Pacific intensified to Category 4 status [and then, Category 5 –Des], making it 22 Category 4 and 5 storms that have formed so far this year. The combination of El Niño, other natural climate cycles and global warming have supercharged this year’s tropical cyclone season in the northern hemisphere to the point where all-time records have been blown away. Specifically, there have now been 21 typhoons and hurricanes in the hemisphere — all but one of which occurred in the Pacific Ocean — that have reached the most intense levels of the Saffir Simpson Hurricane Wind Scale, Category 4 and 5. This beat the past record of 18, set in 2004. One of the strongest El Niño events ever recorded has provided storms with an ample amount of fuel in the form of warm ocean waters across the tropical Pacific, and has also helped squelch tropical activity in the North Atlantic Basin. On average, El Niño years have higher readings on a scale known as the “Accumulated Cyclone Energy”, or ACE, index. This index measures both a storm’s intensity and its lifespan. To date, the ACE index across parts of the Pacific is off the charts, says Philip Klotzbach, a research scientist at Colorado State University. Evidence of El Niño’s influence is strong, considering that only one of the Category 4 or 5 storms in the hemisphere this year occurred in the North Atlantic Ocean. [more]

21 hurricanes and typhoons that shattered records in 2015