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Volcanic ash fall information

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Volcanic ash fall information

How to deal with ash

Weeks after a major volcanic eruption, such as the Mount St Helens May 1980, ash will still be a major headache. Here are some tips drawn from overseas experience to help you cope with volcanic ash, if eruptions should occur.

Keep the ash outside

Lessen the chance of volcanic ash getting into your house by keeping doors and windows closed. Maintain ‘clean’ areas in your homes.


When outside, use a damp cloth over your mouth and nose to filter volcanic ash. This is especially important if you have breathing problems. If you get ash on your skin, wash it off. Make sure you drink water that hasn’t been contaminated by ash if on tank supply you should disconnect until ash has been cleaned or washed off your roof.

Civil Defence is common sense 


Use a yard broom to remove volcanic ash from your roof. The roof can collapse from the weight of accumulated ash especially if it gets wet. If possible, use the vacuum cleaner to remove dust from surfaces. When cleaning surfaces by hand, avoid excessive rubbing. Volcanic ash particles are very abrasive and will cut through material. When cleaning glass or similar surfaces, use a detergent soaked cloth. Dab the surface wiping it will cause abrasions.

Volcanic eruption - people and animals 


Use dust filter or dry cloth over nose and mouth. Those with respiratory conditions should try to keep out of ash fall.


Protect with goggles. Avoid wearing contact lenses as ash can get between the lens and the eye.

Head and shoulders

A scarf around head and neck will also assist.


Keep completely clothed where possible, wrist bands and gloves will assist.


Ankle or calf-length footwear is preferable, seal around ankles if possible.


Protect animal’s food from ash fall. Seek advice about grazing animals. Seek advice about fresh vegetables and fruit. Protect all water supplies store some water as soon as you hear there may be an eruption.


Seek early advice if problems develop.

Motor vehicles (in heavy ash conditions) 


Don’t use washers or wipers. Ash is abrasive. Dust off with a brush.

Air and oil filters

In heavy ash conditions change air filter every 80km and the oil filter regularly.


Seal all window edges with tape.


Clean daily.

Electrical parts

Where possible seal with plastic and tape or ash can cause short circuits.

Ventilation / air conditioning

Don’t use, seal all inlets and outlets, if possible disable.

Speed restrictions

Not more than 30km/hour.

Houses and buildings 


Remove ash by brushing to prevent collapse if the ash begins to accumulate.

Its best to wait until the ash fall has stopped, take care not to fall off. You may have to remove spouting.


Protect from ash, divert if necessary. Don’t flush ash into stormwater drains.


Can be sealed with wide tape if they have gaps.


If on tank supply, remove down pipes or seal outlet hole. Maintain emergency supplies, conserve use.

Electrical Appliances

Turn off air conditioners

Don’t use during ash fall and clean with air or dusting. Remember ash can cause short circuits especially if it gets damp.


Protect as far as possible. Ash can be toxic.


Clean with dusting or dabbing motion, not by wiping.

What “Not to do” if there's an ash fall or a major eruption

  • Don't use your car unnecessarily.
  • Don't go sightseeing
  • Only call relatives who might be affected by the eruption if really necessary if you do call be as brief as possible.


  • If ash begins to fall start dealing with it as early as possible.
  • If you need more information phone Civil Defence.
  • 867 2049 or 0800 653 800 Civil Defence