Tropical cyclone activity in the Northwest Pacific Basin has seen a significant increase since April 2026, highlighted by the emergence of Super Typhoon In-fa, which was active near the Mariana Islands at the end of October. This season has already produced 25 named storms, maintaining a high level of meteorological activity in the region.
Super Typhoon In-fa and Typhoon Champi
Images captured by the Earth Polychromatic Imaging Camera on the DSCOVR satellite showed In-fa churning near the Mariana Islands on October 29, 2026. Simultaneously, the remnants of Typhoon Champi were moving toward Alaska, contributing to a series of storms in the Bering Sea. In-fa marked its fifth impact on the Mariana Islands this year.
The Moderate Resolution Imaging Spectroradiometer on NASA’s Terra satellite recorded In-fa on October 30, when it was positioned just west of the island chain. At this point, In-fa displayed characteristics of an annular storm, noted for its circular shape and large eye, which distinguishes it from typical tropical cyclones that usually have prominent outer rainbands. Meteorologists often refer to these annular storms as “doughnuts” or “truck tires.”
Characteristics of Annular Storms
Annular storms represent a rare subset of tropical cyclones, comprising only 4 percent of such storms in the western North Pacific. These storms typically feature larger eyes, averaging about 45 kilometers (30 miles) in diameter, and tend to retain their strength longer in adverse conditions compared to standard tropical cyclones.
While In-fa still qualified as a tropical cyclone, Champi’s remnants had transitioned into an extratropical storm upon entering the Bering Sea. Tropical cyclones, characterized by their warm cores, are fueled by warm ocean waters, whereas extratropical cyclones possess cold cores and derive energy from temperature differences between air masses. Extratropical storms are known for their development of fronts and large, spiraling cloud bands.
Impact of Typhoon Champi
Champi, which reached maximum sustained winds of nearly 300 kilometers (185 miles) per hour, is considered one of the strongest storms of the season. Despite narrowly avoiding direct hits on Taiwan and Guam, it caused damaging winds and heavy rainfall in both locations, along with impacts in parts of China and Japan. In its transition to an extratropical system, the impacts were felt in Alaska, which experienced high winds and heavy precipitation, although the damage was less severe than that caused by previous storms.
This year, Champi is the fourth ex-typhoon to influence Alaskan weather, following others earlier in the season. According to a climatologist from the University of Alaska Fairbanks, the increased activity in 2026 can be attributed to a strong El Niño, which affects storm trajectories in the Pacific.
The Role of El Niño
El Niño, a climate phenomenon occurring every two to seven years, is characterized by warmer-than-normal water temperatures in parts of the equatorial Pacific. Experts indicate that during this phenomenon, storms are more likely to shift northward rather than continuing westward, leading to more frequent impacts on areas like Guam, the Northern Mariana Islands, and parts of East Asia.
Overall, 2026 has been noted as an especially active year for tropical cyclones in the Pacific, with meteorologists anticipating that the ongoing El Niño will continue to influence this pattern.
NASA Earth Observatory images were utilized in this report, showcasing the dynamic weather patterns occurring in the Pacific region.
Source: NASA
