The Pacific has experienced an unusually active tropical cyclone season in 2026, with powerful storms affecting island communities and bringing severe weather to distant regions. NASA satellite observations captured two remarkable developments in late October: Super Typhoon In-fa displaying an unusually large, well defined eye near the Mariana Islands, while the remnants of Typhoon Champi transformed into an extratropical storm approaching Alaska.
According to NASA’s Earth Observatory, tropical cyclone activity in the Northwest Pacific has remained elevated since April 2026, when Super Typhoon Sinlaku struck Micronesia, Guam and the Northern Mariana Islands. By late October, the basin had recorded 25 named storms.
NASA’s DSCOVR satellite captured the large-scale Pacific weather system on October 29, while its Terra satellite recorded detailed images of In-fa on October 30.
In-fa was unusually intense when NASA’s Terra satellite observed it west of the Mariana Islands. The storm had a nearly circular shape and a large, clearly defined eye, characteristics associated with a rare category of tropical cyclones known as annular storms.
Often described as doughnut shaped storms, annular cyclones generally lack the prominent outer spiral rainbands commonly seen in conventional tropical storms.
According to one analysis, annular storms account for only around 4% of tropical cyclones in the western North Pacific. Their eyes typically measure approximately 45 kilometres across, compared with around 25 kilometres in standard tropical cyclones.
These storms can also maintain their intensity for longer periods under unfavourable atmospheric conditions.
In-fa became the fifth typhoon to affect the Mariana Islands in 2026, adding to an already active season across the western Pacific.
Typhoon Champi Transforms into a Powerful Storm Near Alaska
While In-fa continued as a tropical cyclone, the remnants of Typhoon Champi underwent a major transformation as they moved towards the Bering Sea.
The process, known as extratropical transition, occurs when a tropical cyclone changes into a different type of storm. Tropical cyclones are warm core systems powered by heat and moisture from warm ocean waters. Extratropical cyclones, by contrast, generally have cold cores and draw energy from temperature differences between warm and cold air masses.
These systems often develop weather fronts and enormous, comma shaped cloud formations.
NASA meteorologist Gary Partyka explained that one major feature of extratropical transition is the expansion of a storm’s wind field. This does not necessarily mean stronger winds, but rather that the winds can spread across a much wider area.
In Champi’s case, its remnants became intertwined with an existing midlatitude storm system over the Bering Sea, likely contributing to its intensification.
Champi’s Destructive Journey Across the Pacific
Before reaching Alaskan waters, Champi had travelled through the western Pacific, reaching maximum sustained winds of nearly 300 kilometres per hour.
The powerful typhoon brought damaging winds and heavy rainfall to parts of China and Japan, as well as Taiwan and Guam, despite narrowly avoiding direct impacts on some locations.
When its remnants reached Alaska, the state avoided the catastrophic destruction experienced after ex-typhoon Halong struck in October 2025. However, some areas experienced strong winds, heavy rainfall and snowfall.
According to University of Alaska Fairbanks meteorologist and climatologist Rick Thoman, Champi was the fourth former typhoon to enter Alaskan waters in 2026. It followed Bang-Lang in August, Dujuan in September and Choi-wan in early October.
Approximately 60 former typhoons have affected Alaska since 1970, highlighting the region’s exposure to powerful storms that travel northwards from the Pacific.
Strong El Niño May Be Influencing Pacific Storm Activity
Scientists believe the strong El Niño developing in the Pacific may be contributing to the unusually active cyclone season.
El Niño is a recurring climate phenomenon, generally emerging every two to seven years, characterised by warmer than normal sea surface temperatures across parts of the equatorial Pacific.
In the Northwest Pacific, El Niño can influence storm tracks, making cyclones more likely to curve northwards rather than continuing west towards East and Southeast Asia. This can increase the likelihood of storms moving towards Guam, the Northern Mariana Islands, Japan and the Korean Peninsula.
NASA meteorologists describe 2026 as a particularly active year for Pacific tropical cyclones, increasing the chances of Alaska experiencing storms that undergo extratropical transition.
However, the precise contribution of El Niño to individual storm developments and their paths requires further analysis.
The latest satellite observations demonstrate how tropical storms can evolve into large weather systems capable of affecting regions thousands of kilometres away. With Pacific cyclone activity remaining elevated, scientists continue to monitor changing storm patterns and their potential impacts across the region.