Typhoon Maysak (2015)

Typhoon Maysak (Chedeng)
Typhoon (JMA scale)
Category 5 (Saffir–Simpson scale)
Typhoon Maysak as seen from the International Space Station, on March 31, 2015
Formed	March 26, 2015
Dissipated	April 7, 2015


Highest winds	10-minute sustained: 215 km/h (130 mph) 1-minute sustained: 260 km/h (160 mph)
Lowest pressure	905 mbar (hPa); 26.72 inHg


Fatalities	4–9 total
Damage	$8.5 million (2015 USD)
Areas affected	Federated States of Micronesia, Philippines

Part of the 2015 Pacific typhoon season

Typhoon Maysak, known in the Philippines as Typhoon Chedeng, was an unusually intense early-season tropical cyclone and the most powerful pre-April typhoon on record in the Northwestern Pacific Ocean.^[1]^[2] Maysak affected Yap and Chuuk State in the Federated States of Micronesia, as well as the Philippines.

The fourth named storm of the 2015 Pacific typhoon season, Maysak formed only a few days after the last system near the equator. The system developed into a tropical depression on March 26, and then a named tropical system the next day. According to the JMA, Maysak became the second typhoon of the year on March 28. The typhoon explosively intensified into a Category 5 super typhoon on March 31. After maintaining that intensity for 24 hours, Maysak weakened and made landfall over Luzon, Philippines as a minimal tropical storm, and dissipated shortly afterwards. The name Maysak refers to a species of tree and was contributed by Cambodia.

Maysak was responsible at least four, and as many as nine, deaths in the Federated States of Micronesia alongside extensive damage. Estimates from The Red Cross suggested that there 5,000 people in desperate need of food, water and shelter, and needed emergency assistance. Pacific Maritime Association administrator Melinda Espinosa said "Most concrete structures withstood the fury but everything else was damaged."^[3]

Meteorological history

Map plotting the track and intensity of the storm according to the Saffir–Simpson hurricane wind scale

The origins of Maysak can be tracked back to a low-pressure area formed southwest of Marshall Islands on March 23. It slowly drifted northwestward and became more organised over the next two days. The Joint Typhoon Warning Center (JTWC) reported moderate chances of tropical cyclone formation on March 25.^[4] The next day, the Japan Meteorological Agency (JMA) started tracking the system as a tropical depression.^[5] On March 27, the JTWC started tracking the system as a tropical depression, and designated it 04W.^[6] Moving west-northwestward, the system's center became more consolidated with convective banding becoming wrapped into it. The JTWC upgraded 04W to a tropical storm the same day.^[7] The JMA followed suit later that day, when it was named Maysak.^[8] On March 28, microwave satellite imagery revealed an eye with central dense overcast obscuring most of the feature. The storm was tracking westward along the periphery of a subtropical ridge,^[9] when the JMA further upgraded it to a severe tropical storm.^[10] The eye became more well defined with deep convection persisting along the southern quadrant of the storm. The overcast became more consolidated,^[11] as the JMA upgraded Maysak to a typhoon the same day.^[12]

The eye of Maysak, as seen from the ISS, displaying a pronounced stadium effect.

On its subtropical ridge-driven westerly path, Maysak developed good radial outflow, which was being enhanced by a strong northward flow.^[13] Despite favourable conditions for intensification, the moderate vertical wind shear the system was experiencing initially kept Maysak from rapidly intensifying.^[14] The typhoon continued moving west-northwestward over the next three days. On March 30, Maysak's eye became clearly visible, with convective bands wrapped tightly into the eyewall.^[15] After vertical wind shear became less intense, Maysak rapidly intensified over a period of six hours attaining one-minute maximum sustained winds of 230 km/h (145 mph), making it a Category 4-equivalent typhoon on the SSHWS.^[16] The JTWC reported a 30 km (19 mi) wide eye, displaying the stadium effect. Maysak maintained a very deep, intense convection. By March 31, Maysak further intensified into a Category 5-equivalent super typhoon on the SSHWS, with one-minute sustained wind speeds of 260 km/h (160 mph).^[17] Later, the JMA assessed Maysak as a "violent" typhoon with 10-minute sustained winds of 215 km/h (130 mph) and a central pressure of only 905 mbar (hPa; 26.73 inHg), making Maysak the most intense typhoon ever recorded in the month of March.^[18] Maysak had a nearly symmetric eye with an almost perfect ring of convection around it. It displayed the characteristics of an annular tropical cyclone.^[19] On April 1, the JTWC reported that the eye of Maysak had widened to about 40 km (25 mi) after undergoing an eyewall replacement cycle.^[20] At the same time, the JMA had reported that Maysak had begun weakening.^[21] Satellite imagery had revealed that the ring of convection around the eye, as well as the eye had shown signs of weakening. The JTWC lowered Maysak's winds to 240 km/h (150 mph), making it a Category 4 super typhoon after it had maintained Category 5-equivalent status for 24 hours.^[22]

Upper level environmental conditions began to deteriorate, as dry air entered the typhoon. The JTWC reported that convection had weakened significantly along the southern quadrant of the system by 15:00 UTC on April 1.^[23] Around the same time, Maysak entered the Philippine Area of Responsibility, and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) started tracking the system. Maysak was given the local name Chedeng.^[24] Later that day, more dry air entered Maysak's ring of convection, weakening it further. The overall convective structure of Maysak weakening with most of the intense convection being located only along the northern quadrant of the storm.^[25] The eye widened further to around 50 km (31 mi) on April 2, with dry air wrapping into the center.^[26] Maysak encountered strong wind shear along its western quadrant, which resulted in some slight overall dissipation of deep convection, and the weakening of the eyewall, primarily along the southern quadrant.^[27] The eye of the typhoon became obscured later that day. Most of the convection around the system was sheared off and could be seen clearly in infrared satellite imagery.^[28] Maysak gradually weakened further, and on April 5, it made landfall in Luzon as a minimal tropical storm. It was immediately downgraded to a tropical depression a few hours later, as it lost most of its convection, and finally dissipated the next day in the South China Sea.^[29]

Impact

Typhoon Maysak passing north of Yap on March 31

Federated States of Micronesia

Typhoon Maysak was responsible for extensive damage across the Federated States of Micronesia (FSM), with Chuuk and Yap States suffering the brunt of its impact. Sources differ on the number of fatalities attributed to the cyclone, ranging from four to nine.^[30]^[31] The FSM Government itself reports that five fatalities resulted from the storm, all of which took place on Chuuk.^[32] According to the United States Agency for International Development (USAID), a total of 29,000 people were directly affected by the storm and damage throughout the FSM amounted to $8.5 million.^[30]

The storm first struck Chuuk State on March 29, passing directly over the main island as a Category 1-equivalent typhoon. High winds, measured up to 114 km/h (71 mph) at the local National Weather Service office, downed numerous trees, power lines, and tore off roofs. An estimated 80–90 percent of homes in Chuuk sustained damage.^[33] The storm destroyed at least 830 homes and 37 businesses, displacing 6,760 people. Power to most of the state, including the entirety of Weno, was knocked out and communication was difficult.^[32] Water sources were rendered undrinkable.^[34] Six vessels sunk at the island's port.^[35] Agricultural impact was extensive, with 80 percent of the banana, breadfruit, and taro crops.^[32]

Two days after striking Chuuk, Maysak passed directly over Ulithi atoll and skirted Fais Island at peak intensity, resulting in extensive damage.^[32]^[34] According to Guam Governor Eddie Calvo, winds reached 210 km/h (130 mph) in Ulithi and 160 km/h (100 mph) on Fais.^[35] All structures on Ulithi not made of concrete were severely damaged or destroyed by Maysak's powerful winds.^[36] Power and water supplies to Ulithi were completely lost during the storm.^[37] The entirety of the island's crop were ruined by the typhoon's storm surge, with early estimates indicating that it would be a full year before crops could be planted again.^[35] No fatalities or injuries took place both areas. Though spared a direct hit, Yap proper was also hit hard with reports of airborne debris during the storm.^[34]

Chuuk Governor Johnson Elimo issued a state of emergency on April 1 and stated that international assistance was necessary. Immediate concerns included the possibility of residents starving with most of the state's crops ruined.^[34] The government estimated that residents on Fais and Ulithi would need food rations for 3–6 months following the typhoon.^[37] Debris removal at Chuuk International Airport allowed for flights to the state to resume on April 1.^[35] Emergency assistance across the nation was hampered by the remote and small nature of the islands it comprises. In many instances, communities can only be reached by boat. Further complicating issues was the large number of trees uprooted or downed by the storm which blocked numerous roads.^[38] Generators had been supplied to Ulithi and Fais by April 6, allowing for water pumps to be activated and supply clean water. On April 6, a United States Coast Guard helicopter provided an aerial assessment of the islands affected.^[37] Relief supplies stockpiled by the Micronesian Red Cross were distributed in the immediate aftermath of Maysak; however, these supplies were exhausted by April 8.^[38] On April 9 the Congress of the Federated States of Micronesia held a special two day session at the request of President Manny Mori, which included determination of typhoon relief funds. They announced the allocation of $1.5 million toward relief for Chuuk and Yap States on April 11.^[39]

Several countries, agencies, and non-governmental organizations came to the aid of the FSM in the wake of Maysak, with total humanitarian assistance reaching nearly $2.3 million by April 22.^[30] On April 13, the Government of Australia provided A$100,000 (US$77,000) and two patrol boats for recovery and relief operations.^[40] As an offer of "comfort and support", the Chinese government gave the FSM $500,000 in cash on April 21.^[41]

Philippines

Striking the Philippines as a rapidly weakening system, Maysak had only minimal effects in the country. Across Aurora and Isabela provinces, a total of 2,761 people were directly affected by the storm most of whom were evacuated prior to Maysak's landfall. The Department of Social Welfare and Development reported that ₱300.9 million (US$6.8 million) worth of funds and supplies were available for possible relief efforts. Approximately 28,000 family food packs were prepositioned in warehouses across Luzon. No damage or loss of life was reported; however, four people were injured after huge waves generated by Maysak hit them while they were taking selfies along the shoreline of Dipaculao town in Aurora province on April 4.^[42]^[43] One flight from Ninoy Aquino International Airport was canceled in relation to Maysak.^[44] An overloaded, unregistered ferry capsized off Sulu Province in Mindanao on April 3, resulting in five deaths. The Philippine Coast Guard stated that seas at the time were calm and the sinking likely resulted from overcrowding of the vessel rather than Typhoon Maysak.^[45]