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Ashfall: what to do before, during and after

PHIVOLCS says to cover your nose and mouth with a damp, clean cloth or a gas mask, close the windows and doors, and scrape the ash off the roof as soon as the ashfall tapers. The DOH adds an N95 or double surgical mask, eye protection, and staying indoors.

By Hamza Rivera, updated

Short answer: PHIVOLCS calls ashfall the ash from an eruption cloud falling back to the ground like rain. During it, PHIVOLCS says to cover your nose and mouth with a damp, clean cloth or a gas mask, close the windows and doors, and scrape ash off the roof as soon as the fall tapers. The DOH advises an N95 or double surgical mask, eye protection and staying indoors.

The alert levels and the danger zone are on the volcanic eruption guide, and the other hazards an eruption brings are on the volcanic hazards page. This page is about the ash.

Written for the Philippines. In an emergency here, the number is 911.

What ashfall is

In PHIVOLCS's words, an explosive eruption throws out "thick and dark ash clouds reaching up to thousands of meters high". Those clouds are fine fragments, and after a few minutes the ash "falls back to the ground like rain. This is what we call ashfall." The coarser pieces land near the volcano, and the farther away you are, the finer the ash.

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

PHIVOLCS's Introduction to Volcanoes defines ash as volcanic fragments less than 2 mm across. Carried up in the eruption plume, they settle over the areas downwind of the volcano as a blanket of ashfall.

Source: PHIVOLCS, Introduction to Volcanoes. Read 8 November 2026.

What heavy ashfall does

PHIVOLCS says heavy ashfall can harm people, animals, plants, equipment, engines and structures. Fine volcanic ash is often small enough to breathe in, and it can cause respiratory disease if inhaled over a long period. Its soluble salt can harm plants.

Thick ash on a roof, especially once rain falls on it, could make a house or building collapse. Acid-bearing ash can corrode metal and ruin an air conditioner, freezer, refrigerator, radio, television or computer. It can also damage vehicle engines and cause road accidents. PHIVOLCS's sheet puts it this way: "We cannot stop an ashfall but we can minimize its adverse effects."

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

Before

When an eruption that could bring ash is on the way.

  1. When an eruption that may bring ashfall is coming, listen to the radio for updates.
  2. Get a gas mask or clean cloth for covering the nose ready, with candles, matches, flashlights and extra batteries. PHIVOLCS says to put them somewhere you can reach easily.

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

  1. Keep a list of emergency hotlines, and listen to what the authorities announce.
  2. If you may have to evacuate, prepare a go bag with drinking water, food, clothes, a first aid kit and essential medicine.

Source: DOH Bicol Center for Health Development, DOH Bicol CHD activates Code White Alert, cautions public amid Mt. Bulusan eruption (28 April 2025). Read 8 November 2026.

What else to pack is on the go bag page.

During

While the ash is falling.

  1. Stay calm. Cover your nose and mouth with a damp, clean cloth or a gas mask.
  2. As soon as the ashfall tapers, scrape off the ash that has built up on the roof. PHIVOLCS says this is to prevent collapse.
  3. Listen to the radio for updates on the eruption.
  4. Close all the windows and doors of the house and your car.
  5. Keep pets in their shelter or inside the house, to help them avoid breathing ash.
  6. Cover water containers and food, so ash does not get into them.
  7. Wash all fruit and vegetables thoroughly before eating.
  8. If you are outdoors, look for shelter and wear glasses to protect your eyes. Avoid using contact lenses.
  9. If you are driving, pull to the side of the road and stop if the ashfall is heavy.

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

The DOH's advice to avoid getting sick from the ash:

  1. Stay indoors as much as possible, and keep the doors and windows closed.
  2. Use an N95 face mask or a double surgical mask.
  3. Wear safety goggles or other protective gear for the eyes.
  4. Wear long sleeves and pants that cover the skin.

Source: DOH Bicol Center for Health Development, DOH Bicol CHD activates Code White Alert, cautions public amid Mt. Bulusan eruption (28 April 2025). Read 8 November 2026.

After

Cleaning up without spreading the ash.

  1. After removing the ash, clean the roof and gutter with water to prevent corrosion.
  2. Use a vacuum cleaner, or shake the loose ash off furniture, before dusting it. Cover your nose and mouth while cleaning.
  3. To get ash off the glass windows and doors of the house and the car, hose them down before washing them with soap and lukewarm water.
  4. Use powder detergent to wash clothes that have ash on them.
  5. Shake loose ash off plants before watering them.
  6. Collect the ash and put it somewhere far from water drainage, so it does not clog it.

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

Ash on the skin, from the DOH:

  1. Do not let ash stay on your skin. Bathe or wash right after being out in the ashfall.
  2. Rinse any ash stuck to the skin with clean water and mild soap.
  3. Avoid scratching itchy skin, so it does not get more irritated.

Source: DOH Negros Island Region Center for Health Development, Protektahan ang balat laban sa ashfall (posted 16 March 2026). Read 8 November 2026. The advisory is in Filipino. The lines here are translated.

Health effects, as the DOH states them

The DOH's Negros Island Region office says volcanic ash can irritate the skin and cause itching and rashes, especially in children, older people and people with sensitive skin. Its advice is to stay indoors as much as possible to avoid exposure, and to wear long sleeves, pants and a hat if you need to go out.

Source: DOH Negros Island Region Center for Health Development, Protektahan ang balat laban sa ashfall (posted 16 March 2026). Read 8 November 2026. The advisory is in Filipino. The lines here are translated.

The DOH's Bicol office tells anyone who has symptoms after being exposed to ashfall to consult their nearest health center right away.

Source: DOH Bicol Center for Health Development, DOH Bicol CHD activates Code White Alert, cautions public amid Mt. Bulusan eruption (28 April 2025). Read 8 November 2026.

What the agencies say to cover your face with

PHIVOLCS
A damp, clean cloth or a gas mask over the nose and mouth during ashfall, and the nose and mouth covered while cleaning up.
DOH Bicol
An N95 face mask or a double surgical mask, with safety goggles or other eye protection.

Source: PHIVOLCS, What to do Before, During and After an Ashfall (printed with support from DOST-GIA, CY2002). Read 8 November 2026. Listed on that page as "Ashfall - What to do?", an illustrated sheet. The steps here are its captions.

Source: DOH Bicol Center for Health Development, DOH Bicol CHD activates Code White Alert, cautions public amid Mt. Bulusan eruption (28 April 2025). Read 8 November 2026.

Before the next eruption

PHIVOLCS sets an alert level from 0 to 5 for a restive volcano. The eruption guide reads each level in its words.

The volcanic eruption guide Volcanic hazards The go bag list