Preparing for a storm surge

MANILA, Philippines — The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) warned yesterday of life-threatening storm surges across different provinces due to Typhoon Uwan.

But what is a storm surge, anyway?

“It is an abnormal rise of sea level due to strong winds associated with the tropical cyclone, pushing the surface of the water toward the coasts,” Marcelino Villafuerte II, PAGASA’s deputy administrator for research and development, told The STAR in a message yesterday.

In its 5 p.m. bulletin, PAGASA warned of three-meter storm surges within the next 48 hours over low-lying and coastal areas of Batanes, Cagayan, Isabela, Ilocos Norte, Ilocos Sur, La Union, Pangasinan, Aurora, Zambales, Bataan, Pampanga, Bulacan, Metro Manila, Cavite, Batangas, Quezon, Camarines Norte, Camarines Sur, Catanduanes, Albay, Sorsogon, Northern Samar, Eastern Samar, Dinagat Islands, and Siargao and Bucas Grande Islands.

The term “storm surge” entered public consciousness in 2013, when Typhoon Yolanda, the world’s most powerful storm ever, battered the Philippines.

The country marked the 12th anniversary of Yolanda’s landfall – and devastation – yesterday, as the Visayas still reeled from the onslaught of Typhoon Tino.

In a detailed analysis conducted by the Department of Science and Technology and the Japan Science and Technology Agency in 2015, the team found that the storm surge in Tacloban City during Yolanda reached up to seven meters, equivalent to the height of the second floor of a house.

Even then, “it was difficult to estimate the maximum storm surge height around this area,” the researchers found.

In other parts of Leyte and Samar, the height of the storm surge ranged between three and six meters. One respondent in Barangay Bislig in Tanauan, Leyte, described the flow of the water as akin to a washing machine.

The massive storm surge quickly inundated Leyte, Samar and other provinces, delivering floodwaters with a 200-year return period. In Tacloban, waters “significantly rose” in just 10 minutes. Residents were shellshocked by the catastrophe.

According to the analysis, only 47 percent of respondents understood what a storm surge meant before Yolanda struck. But it was unclear whether these people “accurately” knew its threat.

“Storm surges were explained as ‘dagko nga balod’ or ‘very big waves,’” the study found. “Some people thought that their houses could withstand strong waves, and did not evacuate.”

The analysis added that people would have taken the threat seriously had the storm surge been described as comparable to a tsunami. But Mahar Lagmay, director of the University of the Philippines Resilience Institute, said in a media workshop in 2013 that equating these two terms is dangerous and inaccurate.

Villafuerte said Typhoon Uwan may generate three-meter-high storm surges in Aurora and Isabela, where the cyclone will directly pass.

The 2015 analysis offers a crucial lesson that applies to this day: “Early evacuation before the arrival of a typhoon is definitely important for safe evacuation. Evacuation is needed to finish sufficiently before the typhoon arrives.”

Meanwhile, Assistant Secretary Bernardo Alejandro IV, the deputy administrator of the Office of Civil Defense (OCD), urged PAGASA to “rethink” its early warning systems for better public understanding.

“Our agencies are providing warnings that are science-based. The challenge for OCD and local government units is how to humanize or localize these warnings so the public can easily understand,” Alejandro told ANC’s “Dateline Philippines” on Wednesday, when asked about the lessons learned from the devastation of Typhoon Tino.

Asked for comment, Villafuerte said PAGASA “welcomes suggestions and commits to do our best to improve our services.”