The National Power Corporation (Napocor) announced that it has ordered the spilling of water from the San Roque Dam after water reached 278 meters as provided for under the interim protocol on water release from dams.

This developed as the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) said that a High Pressure Area (HPA) near Hong Kong as well as the southwestward movement of typhoon “Ramil” has slowed down the cyclone’s pace from 17 down to 15 kph Wednesday morning, delaying its landfall to Friday.

With Ramil’s slowdown, residents living in Northern and Central Luzon still have the entire Thursday to evacuate to safer places before it directly hits the country, ramming the provinces in the Ilocos, Cordillera, Cagayan regions as well as the northern part of Central Luzon by Friday morning.

PAGASA Deputy Director Nathaniel Cruz explained that the wind shear or different wind directions of “Ramil” also caused its deceleration, which consequently postponed the expected landfall over Cagayan province to Friday morning, instead of Thursday noon.

In an update, Napocor said that as of 7 a.m. yesterday, water at the San Roque Dam had reached 278 meters and the dam had started spilling water from one gate which was opened by a total of 0.5 meter.

Napocor measured the water inflow at 352 cubic meters per second and the outflow also at 352 cms at the San Roque Dam.

At the Angat Dam, water was recorded to have an elevation of 210.25 meters and thus the gates remained closed.

Based on data from the PAGASA website, the San Roque Dam water elevation has eased to 277.80 meters by 10 a.m. Wednesday with one gate spilling 354 cms.

The Ambuklao Dam has one gate open at one meter and spilling 23 cms with water elevation at 741.90 meters compared to its normal spilling level of 752 meters.

The Pantabangan Dam is spilling 200 cms from a gate that is open by four meters as water has reached 218.46 meters from its normal spilling level of 221 meters.

The Magat Dam has released water at the rate of 606 cms from one gate that is open by a meter as water has reached 190.31 meters from its normal spilling level of 193 meters.

Energy Secretary Angleo Reyes had announced the implementation of the interim protocol while various agencies were asked to give their input to come up with an amended protocol.

The new protocol calls for the issuance of a general warning six hours prior to the release of water from the dam instead of four hours in the old protocol.

The warning will be coursed through to the local government units and the provincial disaster coordinating councils and will be repeated one hour before actual water release.

Flood bulletins, to be issued by PAGASA, will be sent and update of the status of the dams will be distributed every two hours.

The protocol also stated that Napocor will lower the High Water Level of the San Roque Dam by at least two meters from 280 meters to 278 meters “to increase the capability of flood control mitigation function of the dam.”

Dam operator San Roque Power Corporation said that any water stored above 280 meters is purely for flood control and of no value to power generation since 280 meters of water is already enough for use until the next wet season.

Once the water level reaches 278 meters maximum allowable spill level, the dam will commence pre-spilling at 500 cubic meters and the water flow will continuously be monitored.

“If the water level continues to rise despite release at 500 cubic meters, apply proportionate increase rate of water spill taking into consideration the rate of inflow going to the dam and the level of the Agno River downstream,” the protocol said.

In a PAGASA update, Cruz said that Ramil was last spotted at about 510 kilometers east northeast of Aparri in Cagayan while slightly losing its strength of maximum sustained winds of 175 kph near the center and a gustiness of 210 kph as of 10 a.m. on Wednesday.

Anticipating the powerful typhoon, PAGASA hoisted Wednesday morning Storm Signal No. 3 over the northern part of Cagayan, including Calayan and Babuyan groups of islands, as well Batanes, which will begin to experience heavy rains and winds with strength of 100 to 185 kph starting Thursday.

Storm Signal No. 2 was also raised over the rest of Cagayan, Ilocos Norte, Apayao, Abra, Kalinga, and Isabela while Storm Signal No. 1 was declared over Ilocos Sur, Mountain Provincem Ifugao, Benguet, La Union, Nueva Viscaya, Quirino, Aurora, and Northern Quezon including Polilio Islands Wednesday.

The PAGASA official added that by Thursday, the typhoon will begin to close in on Northern Luzon as it approaches Aparri in Cagayan, noting that the typhoon's circulation that measured 800 kilometers in diameter will swathe even the provinces in the northern part of Central Luzon.

He noted that storm surges similar to tsunamis will be felt in the eastern seaboards of Luzon and Visayas like Palanan Bay in Isabela, northern part of Aurora, Camarines Norte, and Catanduanes as well as Northern and Eastern Samar as “Ramil” was expected to inch closer to North Luzon Thursday.

For his part, PAGASA Administrator Prisco Nilo expected the typhoon to start its six-hour passage in Northern Luzon, ramming the Cagayan, Kalinga, and Ilocos Norte on Friday while heading to the South China Sea or about 80 kilometers northeast of Laoag City by tomorrow morning.

He noted that during the typhoon's exodus, provinces like Zambales, Tarlac, and Pampanga will feel stormy weather with strong winds and rains while provinces in the rest of in Central and Southern Luzon including Metro Manila will have minimal rainshowers and occasional gusty winds.

Although the typhoon has already shown indications of weakening, Nilo highlighted the possibility “Ramil” to reach a Super Typhoon intensity considering that the tropical cyclone has been expected to stay a day longer over the seas.

Nilo said that the typhoon will dump around 20 to 25 mm of rainwater in Northern Luzon for the duration six hours starting Friday, which would be comparable to the filling of water in 500 Olympic-size swimming pools within just one hour “if the typhoon will hit a 5,000-hectare area like Quezon City,” which will definitely trigger flashfloods and landslides in North Luzon.

As this developed as 75 new rubber boats will be deployed to Northern Luzon in anticipation of typhoon Ramil, the Department of Interior and Local Government (DILG) said Wednesday.

“The new rubber boats will be immediately deployed to the North which is being threatened with one of the strongest typhoons that we expect this year,” DILG Secretary Ronaldo Puno said.

“We pray that the typhoon will not cause much harm and damage but we must be always be prepared,” he added. (With a report from Jeffrey G. Damicog)