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Tuesday, 14 Jan 2020
A family evacuating to safer grounds as Taal volcano in Tagaytay erupted on Monday. - AP
MANILA, (Philippine Daily Inquirer/ANN): The proposal to cloud seed in areas affected by ashfall from the eruption of the Taal Volcano needs further study, according to the director of the Philippine Institute of Volcanology and Seismology (Phivolcs).
“That has to be studied. In general, cloud [seeding] is a good idea, but how to operationalise it, you really have to study, ” Phivolcs director and Department of Science and Technology (DOST) Undersecretary Dr Renato Solidum said in a press briefing on Tuesday (Jan 14).
Solidum first explained that the rain would be good to wash down the ash caused by the volcanic eruption.
"But the amount of rain that it would produce and where would it fall, obviously there should be an ideal condition where you will cloud seed," added Solidum.
This comes after Senate President Vicente “Tito” Sotto III earlier made his proposal, saying that it would reduce the bad effects of the ashfall.
Asked further if this would lead to a threat of lahar (floods), Solidum answered: “Well, this has to be studied. If you look at it, obviously if there is too much water, it will wash down the ash, but it could also cause lahar because it is washing down the ash."
Lahar, according to the United States Geological Survey, is described as “hot or cold mixture of water and rock fragments that flows down the slopes of a volcano and typically enters a river valley.”
Solidum added that the eruption itself already triggered the process of cloud seeding.
“But then remember, When an eruption occurs, the rise of the warm atmosphere, and the ash as well, can trigger rainfall, ” Solidum explained. - Philippine Daily Inquirer/Asia News Network
By Jeline Malasig
January 14, 2020
Sen. Tito Sotto III speaks to the media. (Senate PRIB)The undersecretary of the Philippine Institute of Volcanology and Seismology did not immediately agree with the suggestion of Sen. Tito Sotto III that cloud seeding should be done in areas affected with Taal Volcano’s ashfall.
Phivolcs Director Renato Solidum said that further study must be done about operationalizing the weather modification activity.
While it may help plants covered in ashfall, it might also bring threats of lahar and flooding in areas near the volcano.
“You have to study how to operationalize cloud seeding,” Solidum said in an interview with CNN Philippines.
He added in a press conference that initiating the activity is difficult if there are no clouds available for seeding in the first place.
“Mahirap mag-cloud seed kung walang cloud na isi-seed mo para umulan,” Solidum said, as quoted by reports.
“Pero kung gaanong kalaking ulan ang mapo-produce n’yan at kung saan tatama ‘yung ulan, obviously, dapat meron kang ideal condition na ika-cloud seed mo,” he added.
Solidum also emphasized that rains might trigger flash floods and lahar.
“Well, this has to be studied. Kung titignan mabuti, obviously, kung masyado maraming tubig, e mawa-wash down ‘yung abo sa gilid, at may banta ng flood or lahar dahil wina-wash down ‘yung mga abo,” he said.
Phivolcs defined lahar as “slurries of volcanic sediment, debris and water that cascade down a volcano’s slopes through rivers and channels.”
It is sometimes called volcanic mudflows or debris flows, the agency added.
Lahar is “mainly generated by torrential rainfall on unconsolidated deposits from a past eruption,” Phivolcs said.
Sotto previously said that cloud seeding should be done in the areas affected by the ashfall brought by the heightened unrest of the Taal Volcano.
“I’m proposing cloud seeding action in the Taal Volcano affected areas and not wait for the rain. I sent word to the executive dept through Bong Go and ES (Executive Secretary) Medialdia. Water solves the ashfall debris,” he said to ABS-CBN.
Sotto also tweeted the same idea on his social media account prior.
Sen. Tito Sotto III tweeting about cloud seeding in areas areas affected by the ashfall of Taal Volcano. (Screenshot by Interaksyon)Many Filipinos disagreed with his suggestion, including a student of Geography from the University of the Philippines-Diliman and a licensed professional teacher.
Jael Gonzales, an undergraduate student, pointed out that cloud seeding is not “instantaneous” in itself.
“Cloud seeding is not instantaneous, any clouds would be blown in the same direction as the debris and gases that came from Taal. Mixed with water, they will produce acid rain and runoff,” he said.
Twitter user @ejgp0627, a licensed teacher, recalled the 1991 eruption of Mt. Pinatubo when heavy rains produced lahar that “destroyed the homes of more than 100,000 people in the area surrounding Pinatubo,” according to the United States Geological Survey.
OMG, Tito Sotto strikes again with a minefield of problematic statements:
1. Cloud seeding = Acid rain / Lahar (remember Pinatubo '91?)
2. Cloud seeding on a no-fly zone?
3. Isn't it Bong Go's already part of the Legislative Dep't? Oh yeah, a seven-hour glitch senator https://t.co/hYSG86TWt0
— The Earl of St. Peters (@ejgp0627) January 13, 2020
USGS also noted that the lahar also caused “more devastation in the (surrounding) lowlands than the eruption itself.”
“In the next four rainy seasons, lahars carried about half of the deposits off the volcano, causing even more destruction in the lowlands than the eruption itself,” the website said.
The Twitter user also pointed out that the vicinity around Taal Volcano, particularly within the 14-kilometer radius from the crater, is considered a “no-fly zone” because of the ash and smoke being emitted.
It could be recalled that the Ninoy Aquino International Airport canceled all of the flights on January 12, Sunday due to the steam-driven eruption where plumes rose as high as 100 meters.
For cloud seeding to be enacted, planes must be deployed in the airspace where clouds are present.
Elmer Caringal, a hydrologist from the Philippine Atmospheric, Geophysical and Astronomical Services Administration, previously said that it could only work if there are “thunderstorm clouds” in the sky.
How does cloud seeding work?
Cloud seeding is the process of adding chemicals, particularly silver iodide or dry ice, to clouds through airplane flares in order to increase rainfall.
It is usually done by the Bureau of Soils and Water Management — an agency under the Agriculture Department — to help areas suffering from drought or dams and reservoirs with low water levels, according to an ABS-CBN News report.
“Cloud seeding works by deliberately sodium chloride or salt into clouds with high moisture content. These are what we call seedable clouds. Once the salt is introduced into the clouds, water vapor attaches to it,” it said.
“They become ice crystals and become bigger. When the cloud can no longer hold on to this, it falls and becomes rain,” the report continued.
It noted that rainfall will begin to commence 30 minutes to one hour after a successful operation.
However, not all clouds can produce sufficient rainfall, PAGASA assistant weather services chief Charmie Monteverde said.
Engineer Teresita Sandoval, chief of BSWM’s water resources management division, revealed that cloud seeding is not an instantaneous process that can be done for the sake of doing it.
“Pupuntahan po nating lahat ‘yung munisipyo, tatangungin natin ‘yung mga technician doon, ‘Ano bang nakatanim? Ano ba ‘yung affected ng cloud seeding? Ano ba ‘yung affected ng drought?’ Kapag sinabi po nila na sampung hektarya lang, hindi naman siguro tama na mag-cloud seeding,” she said.
“Kailangan po natin, andun po sa ating guidelines, kailangan at least 1,000 hectares po ‘yung affected area. At meron po dapat na standing crops… na i-sa-save for total loss,” Sandoval continued.
Published on Jan 13, 2020
The proposal of cloud seeding in areas affected by ashfall from the eruption of the Taal Volcano still needs further study, the director of the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
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