The Northwest Pacific Basin has experienced a significant rise in tropical cyclone activity since April 2026, highlighted by the emergence of Super Typhoon Sinlaku, which severely impacted regions including Micronesia, Guam, and the Northern Mariana Islands. As of late October, the basin remains active, with twenty-five named storms recorded this season.
Super Typhoon In-fa’s Impact
An image captured by the Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) on October 29, 2026, shows Super Typhoon In-fa swirling near the Mariana Islands. Concurrently, the remnants of Typhoon Champi were making their way toward Alaska, amidst a series of storms traversing the Bering Sea. This marks In-fa as the fifth typhoon to affect the Mariana Islands in 2026.
On October 30, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite documented In-fa as it positioned itself just west of the island chain. At this point, the storm exhibited an unusual intensity with a nearly circular formation and a large eye, characteristics indicative of a category known as annular storms. These storms typically lack the distinct outer spiral rainbands associated with traditional tropical cyclones, leading meteorologists to refer to them colloquially as “doughnuts” or “truck tires.”
Characteristics of Annular Storms
According to analyses, annular storms represent a mere 4 percent of tropical cyclones in the western North Pacific. They are characterized by larger eyes, averaging about 45 kilometers in diameter compared to the typical 25 kilometers found in standard tropical cyclones. Annular storms also tend to sustain their strength longer, even under less favorable conditions.
When EPIC captured the earlier image, In-fa was still classified as a tropical cyclone. Meanwhile, the remnants of Typhoon Champi had undergone extratropical transition, transforming into a different storm type as they entered the Bering Sea’s tumultuous storm track. Unlike their tropical counterparts, extratropical cyclones typically feature cold cores and derive energy from temperature differences between warm and cold air masses, often developing fronts and large, comma-shaped cloud bands.
Transition and Effects of Typhoon Champi
Gary Partyka, a meteorologist at NASA’s Goddard Space Flight Center, explained that the transition from tropical to extratropical cyclone often results in an expanded wind field. While this does not necessarily equate to stronger winds, it does mean that the winds impact a larger area. In this instance, it is likely that a midlatitude storm would still have developed over the Bering Sea, even without Champi’s remnants, but the latter contributed to the intensification of the system.
Typhoon Champi had a notable and destructive journey across the West Pacific, achieving maximum sustained winds nearing 300 kilometers per hour. Despite narrowly missing Taiwan and Guam, the typhoon inflicted damage in both regions, along with parts of China and Japan. When Champi’s remnants reached Alaska, they caused high winds and significant rainfall, although the state avoided catastrophic damage similar to that experienced after ex-typhoon Halong in October 2025.
El Niño’s Role in Storm Activity
This year has seen four ex-typhoons enter Alaskan waters, with Champi joining the ranks of Bang-Lang in August, Dujuan in September, and Choi-wan in early October. Rick Thoman, a climatologist at the University of Alaska Fairbanks, noted that only strong El Niño years, such as 1997 and 2015, saw a similar occurrence of three ex-typhoons. Since 1970, approximately 60 ex-typhoons have impacted Alaska.
Partyka described 2026 as an especially active year for tropical cyclones in the Pacific, which has heightened the likelihood of storms undergoing extratropical transitions affecting Alaska. He indicated that the ongoing strong El Niño is likely a contributing factor to this increase in storm activity. The El Niño phenomenon, which occurs every two to seven years, is characterized by warmer-than-normal water temperatures in certain equatorial Pacific regions, influencing the trajectory of storms toward areas like Guam, the Northern Mariana Islands, Japan, and the Korean Peninsula.
NASA Earth Observatory provided the imagery and data used in this report, with the story written by Adam Voiland.
Source: NASA
