Rapid intensification commenced as Sarika turned to the west-northwest towards Luzon, reaching its peak intensity just before making landfall in Aurora early on October 16.

Sarika maintained its strength for the rest of the day and made landfall in Hainan province in China on October 18.

Turning to the northwest, Sarika weakened quickly as it emerged into the Gulf of Tonkin, before moving onshore once again in Guangxi province on October 19.

In particular, Sarika was the strongest October typhoon to hit Hainan since 1971, where nearly 6,000 houses were damaged, 130,000 people lost access to telecommunications services, and almost 381,000 hectares (940,000 acres) of banana, cassava, papaya, and rubber crops were impacted.

Sarika was first noted by the United States-based Joint Typhoon Warning Center (JTWC) as a disorganized tropical disturbance on October 11, while it was about 1,050 km (650 mi) southeast of Manila.

[2] The system quickly consolidated within a favorable environment of low wind shear and high sea surface temperatures of about 30 °C (86 °F), leading the JTWC to issue a Tropical Cyclone Formation Alert.

[3] By 00:00 UTC on October 13, the system's low-level circulation center became increasingly symmetric as it tracked northwestwards and the Japan Meteorological Agency (JMA) upgraded the disturbance to a tropical depression.

However, the system managed to intensify into a tropical storm by 18:00 UTC on October 13 as it traveled west-northwestwards along a subtropical ridge.

[9][nb 3] The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), which had been tracking the storm since October 12, assigned it the local name Karen.

[4] As Sarika traversed warm seas with surface temperatures reaching 31 °C (88 °F),[13] the system developed a small, well-defined eye that was apparent on both infrared and microwave satellite imagery, signalling the onset of rapid intensification.

[14] Sarika reached peak intensity as a very strong typhoon at 18:00 UTC on October 15, assessed by the JMA to have sustained winds of 175 km/h (109 mph) and a minimum pressure of 935 hPa (27.61 inHg).

[16] Significant weakening occurred in the six hours that Sarika traversed Luzon as the mountainous terrain disrupted its circulation,[17] with the JMA and JTWC estimating that winds fell to 140 km/h (87 mph).

[4][7] The system recovered a ragged eye as it continued west-northwest under the influence the subtropical ridge,[18] and exited the Philippine Area of Responsibility on October 16.

[19] Despite continued favorable conditions, Sarika struggled to reintensify as its eye remained ragged,[20] with the JMA assessing that it weakened further to a severe tropical storm at 00:00 UTC on October 17.

[20] At 01:50 UTC on October 18, Sarika made landfall on Hainan Island near Hele, Wanning with winds of 110 km/h (68 mph) according to the JMA.

[22] Sarika's convective structure continued to fall apart,[23] and the system weakened into a tropical depression prior to its final landfall near Fangchenggang, Guangxi at 06:10 UTC on October 19.

A total of 39,934 people across the Ilocos, Cagayan Valley, Central Luzon, Calabarzon, and Bicol administrative regions were evacuated.

[25] The National Disaster Risk Reduction and Management Council (NDRRMC) was placed on red alert on October 15, requiring all associated agencies to be fully staffed and prepared.

[33] On October 18, as Sarika moved away from Hong Kong, the HKO replaced the tropical cyclone warnings with a Strong Monsoon Signal.

[40][22] In Guangdong, authorities enacted a Level II emergency response,[22] with storm surge expected to be enhanced by a concurrent high tide.

[48] Farmers in Hải Phòng rushed to harvest 23,000 hectares (57,000 acres) of rice fields before the typhoon's rainbands arrived.

[53][nb 5] Significant crop damage occurred in the Philippines from the combined effects of Sarika and Typhoon Haima, which struck Northern Luzon a week later.

[58] The entire island experienced torrential rainfall from October 17 to 20, peaking at 548 mm (21.6 in) at Baitang Reservoir in Ding'an County.

[35] Wanning, the landfall point, experienced storm surge, heavy rains, and strong winds that felled several trees.

Nearby, large-scale power outages occurred in the urban center of Qionghai, and the main highway into the city was blocked by floodwaters.

[62] Strong winds generated heavy waves along the coast of Sanya, attracting curious onlookers who had to be escorted away by police and government staff for their safety.

[65] Strong winds damaged 356 base stations in Zhanjiang, requiring 666 support personnel to be dispatched to conduct repair works.

[74][nb 6] After Sarika left the Philippines, the NDRRMC activated the National Response Cluster to coordinate disaster relief.

[76] Two months after the storm, the European Commission released €328,000 (US$363,000) in humanitarian aid funding to assist with meeting the immediate needs of those affected by typhoons Sarika and Haima.

[78] In Hainan, as the rain and wind died down, 2,128 police officers and soldiers were activated to conduct disaster relief.