Tropical Storm Bolaven, known in the Philippines as Tropical Storm Agaton, was an early-season tropical cyclone that affected southern parts of the Philippines in January 2018. The first named storm of the 2018 Pacific typhoon season, Bolaven formed as a tropical depression near Palau on December 29, 2017. The system moved generally westwards without intensifying and made landfall over northeastern Mindanao on January 1, 2018. The depression spent the next day traversing the Philippines, making four more landfalls in the Visayas and one in Palawan. The system strengthened into a tropical storm on January 3 as it entered the South China Sea, receiving the name Bolaven. However, Bolaven weakened back to a tropical depression just a day later amid a marginal environment and dissipated on January 4 east of Vietnam. Bolaven brought heavy rain to areas that had been recently impacted by tropical storms Kai-tak and Tembin. More than 230,000 families in the Philippines were affected and at least 11,000 people sought shelter in evacuation centers. Floods and landslides killed four people across the country, while damaging houses and blocking roads. Maritime transport was greatly disrupted, with rough seas stranding over 3,600 people in various ports. Schools across the country were also shut at various points between January 1 and 3. Economic losses in the Philippines reached ₱554.7 million (US$ million), mostly caused by crop damage. Meteorological history On December 29, 2017, the Japan Meteorological Agency (JMA) began to track a tropical depression about 370 km (230 mi) east of Palau. The system moved northwest for about half a day before turning to the west on December 30. Initially broad and ill-defined, the system began to organize slowly on January 1, 2018, as evidenced by increased thunderstorm activity and banding features. This prompted the United States-based Joint Typhoon Warning Center (JTWC) and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) to upgrade the system to a tropical depression; the latter gave it the local name Agaton. At this time, the system was tracking quickly west under the influence of a subtropical ridge. The depression reached the Philippines on January 1, making landfall over Bucas Grande at 17:00 UTC, then at Claver, Surigao del Norte at 17:15 UTC. The system crossed the Bohol Sea before making a third landfall near Jagna, Bohol at 20:00 UTC, a fourth in Santander, Cebu at 21:00 UTC, and a fifth in Bais, Negros Oriental