Summary Points
Northwest Pacific activity remained unusually high, with 25 named storms by October.
Super Typhoon In-fa displayed rare annular structure near Mariana Islands October 30.
Champi battered Asia before transitioning, helping intensify a sprawling Bering Sea storm.
Strong El Niño likely redirected storms northward, increasing Alaska’s exposure.
The Pacific’s Busy Storm Season
The Northwest Pacific has stayed unusually active since April 2026, when Super Typhoon Sinlaku struck Micronesia, Guam and the Northern Mariana Islands. By late October, 25 named storms had formed in the basin, and the season was still producing major systems.
Two storms showed how far the effects of Pacific cyclones can reach. On Oct. 29, NASA’s DSCOVR satellite captured Super Typhoon In-fa churning near the Mariana Islands. At the same time, the remnants of Typhoon Champi were moving toward Alaska, where they became part of a powerful midlatitude storm system.
The scenes offered a striking view of a busy season. They also showed why a storm’s identity can change as it travels: In-fa remained tropical, while Champi had transformed into an extratropical cyclone.
In-fa’s unusual structure
NASA’s Earth Polychromatic Imaging Camera, or EPIC, captured In-fa from space on Oct. 29. The next day, the MODIS instrument aboard NASA’s Terra satellite photographed the typhoon just west of the Mariana Islands. In-fa was the fifth typhoon to affect the island chain this year.
The Terra image showed a nearly circular storm with a large, clear eye. That pattern is associated with a rare type of tropical cyclone called an annular storm. Unlike typical cyclones, annular storms usually have few prominent outer rainbands, the spiral-shaped bands of clouds and rain that wrap around many storms. Their smooth, ringlike appearance has earned them the nicknames “doughnuts” and “truck tires.”
Annular storms account for about 4% of tropical cyclones in the western North Pacific, according to published research. Their eyes average about 45 kilometers (30 miles) across, compared with roughly 25 kilometers for standard tropical cyclones. They can also maintain their strength longer when conditions become less favorable.
Satellite images make these structural details visible across broad areas of ocean that are difficult to observe directly. But an image is one piece of the forecasting picture, not a complete measure of danger. Forecasters combine satellite observations with other data and analysis to track a storm’s position, intensity and likely path. The images help show what a storm looks like; they do not, by themselves, determine what impacts communities will face.
Champi’s journey from typhoon to Alaska storm
Champi followed a different path. After a destructive trek through the western Pacific, the typhoon reached maximum sustained winds of nearly 300 kilometers per hour (185 mph). It narrowly skirted Taiwan and Guam, but still brought damaging winds and heavy rain to both, as well as parts of China and Japan.
By the time its remnants reached the Bering Sea, Champi had undergone extratropical transition. Tropical cyclones draw energy from warm ocean water and have warm cores. Extratropical cyclones, by contrast, typically have cold cores and gain energy from sharp temperature differences between air masses.
The change often alters a storm’s appearance and reach. Extratropical systems commonly develop fronts and broad, comma-shaped cloud bands. Their wind fields can also expand: Winds do not necessarily become stronger, but they can affect a much larger area. Champi’s remnants became intertwined with a midlatitude storm in the Bering Sea and likely helped intensify it. A storm system would probably have been present in the region anyway, but Champi added to its development.
Alaska avoided the catastrophic damage seen after ex-typhoon Halong struck in October 2025. Still, reports described high winds, heavy rain and snowfall in some areas. Champi was the fourth former typhoon to enter Alaskan waters this year, following Bang-Lang in August, Dujuan in September and Choi-wan in early October. About 60 ex-typhoons have affected the state since 1970.
The season’s pattern may have increased Alaska’s exposure. A strong El Niño is underway in the Pacific, and meteorologists describe it as a likely contributor to the basin’s heightened activity. El Niño occurs when waters in parts of the equatorial Pacific become warmer than usual. In the Northwest Pacific, it can favor storm tracks that curve north rather than continue west toward East and Southeast Asia. That can bring more storms toward Guam, the Northern Mariana Islands, Japan and the Korean Peninsula.
The connection is not a guarantee that El Niño will produce a particular storm or track. Seasonal climate patterns influence the odds, while individual storms still depend on changing conditions. This year, the combination of frequent typhoons, a northward-reaching storm track and Alaska’s active Bering Sea weather made for an especially consequential autumn.
Together, In-fa and Champi illustrate the Pacific’s wide-ranging storm season. One remained a powerful tropical cyclone near the Marianas. The other crossed into a different kind of weather system and helped shape conditions thousands of kilometers away.
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