Super Typhoon Halong was undergoing an eyewall replacement on August 4, 2014 when the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of the storm. In this image, the eye appears distinct but partially cloud-filled and the bulk of the strongest bands of thunderstorms are over the southern quadrant of the storm.
The Joint Typhoon Warning Center (JTWC) noted that microwave satellite imagery also suggested an eyewall replacement. That is when thunderstorms that circle the eye of a powerful thunderstorm are replaced by new thunderstorms, and occurs as a new eye begins to develop around an old eye. Eyewall replacements often correlate to a weakening trend – and such was the case for Halong. On August 2, the storm was a powerful Category 5 Super Typhoon with a 10 nautical mile (11.5 mi/18.5 km) wide eye. On August 4, however, Super Typhoon Halong’s maximum sustained winds had dropped to about 120.8 mph(190.4 km/h), dropping it to a Category Two hurricane on the Saffir-Simpson Hurricane Wind Scale.
Halong formed from a system first identified near Chuuk on July 26. By July 29 it had become a tropical storm, and was given the name Tropical Storm Halong. It impacted Guam at Tropical Storm strength on July 30, and then began rapid strengthening. By August 2 it had gone from a minimal typhoon with 85 mph/137 km/h winds to a super-typhoon with winds of up to 150 mph (241 km/h) in just 24 hours.
After the eyewall replacement cycle on August 4, Halong continued to weaken as it bore down upon Japan. It made landfall in the early morning hours of August 10 near the city of Aki on the island of Shikoku with maximum sustained winds of 75 mph (121 km/h) – a weak Category 1 Hurricane. About four hours later, Halong had crossed the Seto Inland Sea, and made a second landfall in the city of Ako on the island of Honshu at tropical storm strength. It drenched Japan with strong winds torrential rain. Mie Prefecture reported an all-time record rainfall, with nearly 17 in (432 mm) of rain falling in just 24 hours – but that was almost nothing compared with the Yanase observation site in Kochi Prefecture, which reported 35 inches (over 900 mm) of rain.
Damage to Japan was substantial. The rain caused flooding, and winds damaged homes and downed power lines. A tornado spawned by the storm was reported to have damaged 342 homes in Tochigi Prefecture on Honshu Island. Ten people were reportedly killed by the storm in Japan, and two people were reported killed in the Philippines from monsoonal rain caused by the storm’s outer bands.