Recent Events

Tropical Storm Sendong (Washi)

Meteorological Report:
Meteorological REPORT of Tropical Storm SENDONG (Washi)-Initial assessment

Tropical Storm Sendong (Washi) brings death and flooding into the Southern Philippines - 20 December, 2011.

On December 15, a Tropical Depression entered the Philippine Area of Responsibility (PAR), named Sendong by the Philippine Atmospheric, Geophysical & Astronomical Services Administration (PAGASA) named. After crossing Palau, the Japanese meteorological Agency (JMA) upgraded the system to a tropical storm naming it Washi. The tropical storm posed a rather unusual threat on the Philippines, as it headed for the often spared south of the country.


 Figure 1: Satellite image (source: NASA)

On December 16, around 4:00 p.m., Sendong made landfall in the vicinity of Hinatuan, over Surigao de Sur, a province in Mindanao. Several hours later, Sendong entered the Sulu Sea and regained its strength quickly due to slight land interaction with Mindanao. Late on December 17, Sendong crossed Palawan arriving into the South China Sea. On December 18, Sendong made its second landfall around 4:00 p.m. in the vicinity of Puerto Princesa City, Palawan, before heading towards the west of Philippine Sea and exiting the PAR late that day moving towards Vietnam.


Figure 2: Cyclone Track (source:

According to the National Disaster Risk Reduction & Management Council (NDRRMC), Sendong has caused at least 957 fatalities, and 49 people are officially listed as missing. The majority of the deaths were in the cities of Iligan and Cagayan de Oro. Five people were killed in a landslide, but all others died in flash flooding. More than 2,000 have been rescued, according to the Armed Forces of the Philippines. Officials were also investigating reports that an entire village was swept away. The flash flooding occurred overnight, following 10 hours of rain, compounded by overflowing rivers and tributaries. In some areas, up to 20 centimeters of rain fell in 24 hours. At least 20,000 people were staying in 10 evacuation centers in Cagayan de Oro.


Figure 3: DHI's real-time monitoring provides up-to-date information on wind and rainfall all over the Philippines. The heavy rain measured by TRMM satellite on December 17 is represented by the blue colours (see left panel legend).

More than 338,000 persons have been affected in 13 provinces (30 municipalities) and 10,345 houses have been damaged as reported by the National Disaster Risk Reduction & Management Council (NDRRMC). The estimated agricultural damage amounts to almost 2 million PHP.


Figure 4: Rainfall and event category details of affected municipalities on December 17, 2011. DHI's real-time event monitoring is categorized according to the 24hr accumulated rainfall amount and their recurrence interval (10, 15 or 20 years) for each municipality.

PAGASA has alerted that fishing boats and other small sea crafts over the seaboards of Luzon and Eastern Visayas are advised not to venture out into the sea due to big waves generated by the monsoon surge enhanced by tropical storm Sendong.