Lost in transmission

At 11 a.m. last Tuesday, the weather bureau issued an advisory on rainfall in several areas, with the possibility of floods and landslides.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration attributed the rainfall to the “shear line” and the “intertropical convergence zone” or ITCZ. PAGASA said it was also monitoring a low-pressure area (LPA) that could develop into a tropical depression within 72 hours, to be named Paeng.

On Wednesday, PAGASA said the shear line and the “trough” of the LPA, which could develop into a tropical depression within 24 hours, were affecting parts of the Visayas and Mindanao.

PAGASA warned that the combination of the shear line and the LPA trough would bring “moderate to heavy with at times intense rain” over Metro Manila and Calabarzon.

“Light to moderate with at times heavy rain” would prevail over Central Luzon, Bicol region, Eastern Visayas, Caraga and Davao region, the weather experts added. Flooding and rain-induced landslides were possible, PAGASA warned.

So yes, the weather experts did issue regular advisories and warnings about Paeng. But the message must have gotten lost in transmission.

Also, the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM), which includes Maguindanao, was not specifically mentioned in the advisories.

And I bet there were many people who tuned out of the weather report upon hearing “shear line,” the ICTZ and the “trough” of the LPA. The terms were weather gobbledygook for ordinary folks.

I googled the meanings. The shear line is where warm and cold air converge. The trough “is an elongated area of relatively low pressure extending from the center of a region of low pressure.” Got it? Neither did I.

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It didn’t help that Paeng was classified first as a mere tropical depression, and then a tropical storm as it intensified. This was probably because its peak winds of 95 kilometers per hour did not meet the classification of a typhoon. People tend to go on high alert for disaster only when an approaching tropical cyclone is described as a super typhoon.

Many people aren’t even sure what to make of a rainfall alert described as “light to moderate… at times heavy” or “moderate to heavy… at times intense.” We must be such optimists when it comes to weather: we pick the lighter end of the warning and go on with life accordingly.

The government will need to work out a clearer way of communicating the risks posed by weather disturbances. We became familiar with storm surges only after a powerful one struck Manila Bay in 2011, devastating bayfront properties and causing massive flooding from Roxas Boulevard to Taft Avenue. This was followed by the surges of Super Typhoon Yolanda, which flattened much of Eastern Visayas also at around this time of year.

Yolanda at least made landfall after Undas was over, in the first week of November 2013. This time, plans for the long weekend for the days of the dead have been ruined as flights, ship voyages and bus trips were suspended beginning Friday. The North and South Cemeteries in Manila, which were reopened for the first time since the pandemic for Undas, were shut down by the city government over the weekend.

On Saturday afternoon I went to a mall near my home. It managed to push through with a Halloween program for kids, but the rain refused to stop and foot traffic was dismal on an Undas weekend. At 5 p.m., the mall closed, five hours ahead of its usual schedule.

As the wind blew away umbrellas, employees rushing to go home squeezed into whatever public transport was available. Drivers allowed some passengers to sit even along what passes for an aisle in the traditional jeepney.

The early mall closure was prudent. Throughout Saturday night, as people braced for a warning about Paeng directly hitting Metro Manila by 11 p.m., the rain refused to stop. And while the wind did not approach the strength of Yolanda or Milenyo, it was still strong enough to break tree branches and damage roofs.

The incessant rainfall was reminiscent of Ondoy, which also hit Metro Manila as a Category 1 storm when it turned out to be the second most destructive tropical cyclone in the 2009 typhoon season in the Pacific. (Yolanda, in contrast, made landfall as a Category 5 howler.)

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Paeng had not yet made landfall when people in Mindanao began experiencing the heavier end of the rainfall forecast beginning Thursday night.

People in Maguindanao said they were surprised by the unusually heavy rainfall that hit the province, which unleashed killer landslides and cataclysmic flooding. As of yesterday, the official death toll was 55, with about 40 of the fatalities from Maguindanao. At least 20 more were missing.

What happened? I listened to a press briefing on Saturday afternoon, during which a PAGASA representative gave an explanation – or tried to, anyway.

Unlike math, I loved my science subjects. But the best I could make of PAGASA’s explanation, sprinkled liberally with references to shear lines and troughs, was that Paeng sucked in the heavy rainclouds from around its path, and it was Maguindanao’s sheer bad luck that those clouds dumped much of their precipitation on the province.

PAGASA, as far as I know, already has enough Doppler radars to measure and predict with some accuracy the amount of rainfall spawned by monsoons, ITCZs, LPAs and tropical cyclones. If the amount of rainfall can be predicted, so can the likelihood of flooding and landslides.

Throughout Saturday, the National Disaster Risk Reduction and Management Council regularly sent out color-coded rainfall and flooding alerts through text messages.

We don’t know if such alerts were received in Maguindanao and the rest of the BARMM before Paeng made landfall.

As the province grapples with the grievous death toll, there are suggestions to make storm warning systems more relatable to the public. This is to encourage preparedness and timely evacuation.

People can quickly understand, for example, a warning that an approaching weather disturbance could have the same impact as Ondoy and Pepeng, or the force of Yolanda and Pablo, or last year’s Odette, which razed… Siargao.

Typhoon prediction has far more accuracy than earthquake tracking. Even if the worst does not materialize, at least no one will be sorry for preparedness. Accurate warnings are possible, but their urgency must be properly transmitted and authorities alerted.

On top of closer coordination between weather experts and local government executives, we need to make shear lines and troughs understandable to every Juan and Juana.