Reports show that Sendong hit ground by about 4 o'clock in the afternoon (severe weather bulletin no. 4) in Hinatuan, Surigao del Sur, unleashing heavy rains as many as 200 mm (according to Pagasa) when in fact, according to NASA and Japanese Aerospace Exploration Agency, Sendong (international code name Washi) dumped 400 mm of rains, 26 mm less than Ondoy.
Early in the morning of December 16, 2011, PAGASA issued its regular weather bulletin. Its severe weather bulletin no. 4 reported that a new Typhoon, codenamed “Senyong” was expected to make landfall over at Hinatuan, Surigao del Sur with maximum sustained winds of sixty five kilometers per hour near the center and gustiness of up to 80 kph. The weather bureau forecasted it to move West north west at speeds of up to twenty two kph.
Compared with other tropical cyclones which hit the country in the past, Sendong was a relative weakling. It does not have the wind power of an Ondoy nor that of the 1991 Typhoon Uring which killed an estimated 5-8,000 people.
Pagasa even predicted that rains would only amount to 10-25 mm per hour within the 400 kilometer radius of the storm. This is extremely off--when as early as December 14, the Japanese weather bureau already predicted that the typhoon will bring in more than 200-400 mm of rain.
That explains why Pagasa only declared Signal number two over the provinces of Surigao Del Norte,Siargao Island,Surigao Del Sur,Dinagat Province,Agusan Provinces, Bukidnon, Davao del Norte, Davao Oriental,Compostela Valley and Camiguin island.[i]
Pagasa did not expect that Typhoon Sendong would actually create havoc or destruction to Mindanao.
Inspite of the weather bulletins issued by Pagasa, local government officials say there was no alert warning given to them as to the severity of the typhoon. Residents were advised to stay at home.
Sendong made landfall at around 4 o’clock in the afternoon in Hinatuan, Surigao del Sur. After soaking the town with more than 25 mm of rain, Sendong moved stealthly towards other provinces in Northern Mindanao, packing more than 200 mm of rains in its way.
On Saturday morning, residents of Bukidnon experienced the wrath of the Storm. Sendong unleashed more of his power, strong winds and heavy rains poured down on the city of Valencia. The Pulangi river spilled over, destroying the bridge that connects Bukidnon going to Davao City. Houses along the river got swept away by raging flood waters.[ii]
NASA said what caused the devastation was "poor warnings, deforestation, and weak construction". see link:
Areas mentioned that were affected were heavily logged areas such as Bukidnon, CDO, Iligan and Surigao.
Illegally cut logs barred normal water flows from the mountains, causing rivers to swell to as high as 15 feet. This caused siltration and erosion which, along with raging floods from the mountains and swelling rivers, spilled over riverine communities and even those near coastlines.
This calamity exposed the continuous illegal activities of loggers in the area, and to think that this area is the territory of Presidential adviser on Climate Change Nereus Acosta.