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Actions to take for ash fall?

| Households | Businesses | Communities | Ash clean up |

Everyone in an ash fall zone will be exposed to the effects of volcanic ash. Tiny volcanic ash can infiltrate all but the most tightly sealed buildings and machinery and is often small enough (less than 10 microns) to be inhaled deeply into the lungs. Ash fall over extensive areas can prevent travel for days because of poor visibility, slippery roads, and damage to vehicles. Power outages may occur before, during, and after an ash fall either due to equipment failure or because power facilities are temporarily shut down to prevent damage. Afterwards, wind and human activity can stir up ash for weeks to years.

In most situations, acting on a few general principles will reduce the effects of ash and make clean-up operations easier. These principles apply to households, businesses, and communities.

General principles

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Households || Items to stock || Preparedness actions || Durning ashfall || Why clean up? || Precautions || Outside || Inside || Vehicles ||

Household actions to take: Introduction

This section aims to promote the safety of those who experience volcanic ashfall. It details procedures to follow if warning of a volcanic ashfall is given, recommends what to do during ash fall, and what methods are most effective for cleaning up volcanic ash after the event. This information is primarily from a pamphlet, Guidelines on preparedness before, during, and after an ashfall, prepared by the International Volcanic Health Hazard Network (IVHHN) and others.

Essential items to stock before an ash fall

A sustained ash fall may keep people housebound for hours or even days. Keep these items in your home in case of an ash fall:

Actions to be taken in preparedness

What to do if volcanic ash is falling

Why should we clean up the ash?

Volcanic ash is a great nuisance and gets everywhere in the house and office, including inside televisions, computers, cameras and other valuable equipment, where it can cause irreparable damage. Ash is different from ordinary house dust. Its sharp, crystalline structure causes it to scratch and abrade surfaces when it is removed by wiping or brushing. In wet weather the ash deposits are dampened down and the air can be clear, but in drier weather ash can easily be stirred up and remobilised by wind and traffic. As a result suspended dust levels become much higher and can be at levels potentially harmful to health. Rainfall and wind are effective in removing the ash and grass and other plants will eventually bind it to the soil, but with large ash falls this process is too slow and the ash must be cleaned up and taken away from populated areas. In addition, wind may also bring ash into areas which were previously clean so ash may be present in the environment for months or even years following an eruption.

What precautions should be taken before cleaning up ash?

Those undertaking clean-up operations should always wear effective dust masks (see recommended masks from the International Volcanic Health Hazard Network). In fine-ash environments, wear goggles or corrective eyeglasses instead of contact lenses to protect eyes from irritation. Lightly water down the ash deposits before they are removed by shovelling, being careful not to excessively wet the deposits on roofs, causing excess loading and danger of collapse. Dry brushing can produce very high exposure levels and should be avoided. Use extra precaution on ladders and roofs. The ash makes surfaces much more slippery, consequently many people have died from falls while cleaning ash from their roofs. Be aware of the extra load caused by standing on an already overloaded roof - tread carefully. It is preferable to clean roofs before more than a few centimetres of ash has accumulated. Where possible use a harness.

Cleaning up: outside

Keep ash out of buildings, machinery, vehicles, downspouts, water supplies, and wastewater systems (for example, storm drains) as much as possible. The most effective method to prevent ash-induced damage to machinery is to shut down, close off or seal equipment until ash is removed from the immediate environment, though this may not be practical in all cases. Coordinate clean-up activities with your neighbours and community-wide operations. After an ash fall, remove ash from roofs in a timely manner to prevent streets from being repetitively cleaned.


Cleaning up: inside

In general, surfaces should be vacuumed to remove as much ash as possible from carpets, furniture, office equipment, appliances, and other items. Portable vacuum systems equipped with high-efficiency particulate filtering systems are recommended whenever possible. The severity of ash intrusion depends on the integrity of windows and entrances, the air intake features, and the care exercised to control the transport of ash into a building or home via shoes and clothing. Care should also be taken to avoid further contamination during the emptying, cleaning, and maintenance of vacuum equipment. In hot climates, where windows are permanently open, or absent, clean up of houses may be needed several times per day. Clean up inside should only be undertaken after the outside areas have been well cleared.
ash cleanup inside cleaning up ash inside


Clean windscreen wipers before using them on the windscreen to avoid scratching cleaing up a vehicle wiper blade

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Businesses || Preparedness planning || Resources ||

Like other natural emergencies, volcanic ash falls are unplanned events that can affect businesses. Ash fall often leads to a temporary shutdown of business operations (hours to days or longer), and may cause physical damage to buildings, equipment, computers, machinery, vehicles, inventory, and supplies. Furthermore, many explosive eruptions over a period of weeks to months can result in repeated ash falls that require costly cleanup operations after each event. Making a general plan to deal emergencies and a specific plan for ash fall is one of the most important steps to take to mitigate the potential effects of ash and improve the response and recovery of a business to ash fall. Resources are available elsewhere for developing emergency and contingency plans (for example, see a planning guide from FEMA).

During non-eruptive periods, businesses and organizations should consider their vulnerability to volcanic ash falls. Once the vulnerability has been assessed, mitigation strategies can be developed. Three types of approaches can be used (Johnston and Becker, 2001):

Preparedness planning

Experience with ash falls from around the world suggest the following emergency planning measures for ash fall:


Emergency Management Guide for Business and Industry, a step-by-step approach to emergency planning, response, and recovery for companies of all sizes. This guide was produced by the Federal Emergency Management Agency (FEMA) and supported by many private companies and associations representing business and industry (see guide for list).

One-page (front and back) handout prepared by the Emergency Management Division, Washington State, U.S., and U.S. Geolgoical Survey

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Communities || Local preparedness plan ||

Unless a community already has experience with volcanic ash fall, local governments and public organizations are typically not prepared for a rain of gritty ash. After having dealt with the ash fall from the 1980 eruption of Mount St. Helens, communities in Washington and Oregon clearly recognized the need for local emergency plans and emergency public information plans for future ash falls from Mount St. Helens or other nearby volcanoes (FEMA, 1984). According to their experience, such a plan does not have to specifically deal with volcanoes, but can be written to deal with a wide variety of natural emergencies (see recommendations of plan).

Removing and disposing ash are probably the biggest challenges for cities and communities that may experience ash fall. Volcanic ash needs to be removed from urban areas even after a fall of only a few millimeters, and notification of an impending ash fall may allow for less than an hour of final preparation if such a notification comes at all. A number of factors will influence the removal methods employed, the ease with which ash can be removed, and the cost of any clean-up operation. These include ash thickness and grain-size and the availability of equipment. Removal of ash from roads was undertaken by a number of public works departments after the 1980 Mount St Helens eruption. Few, if any, of these organizations had developed plans for ash-removal prior to the cataclysmic eruption even after two months of significant activity at the volcano. Furthermore, little knowledge was available on how to undertake such a massive cleanup.

Dealing with ash fall effectively in communities requires careful planning and coordination among public agencies, businesses, landowners, and the public both in areas affected by ash fall and beyond. Many of the planning measures identified for businesses above can be adopted for community and public facilities, including hospitals, buildings, power stations and equipment, and water-supply and waste-water treatment facilities.

Recommendations for a local preparedness plan (modified from FEMA, 1984)

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Baxter, P.J., 1986, Preventive Health Measures in Volcanic Eruptions. American Journal of Public Health 76 (1986)Supplement: 84-90.

Baxter, P.J. and Maynard, R.L., 1998, Health criteria for reoccupation of ashfall areas in Montserrat. October 1998.

Blong, R.J., 1984, Volcanic hazards: a sourcebook on the effects of eruptions: Academic Press, Australia, 424 p.

Cascades Volcano Observatory and Washington State Emergency Management Division, 1999, Volcanic ashfall: how to be prepared for an ashfall: U.S. Geological Survey and Washington Military Department Emergency Management Division, 1 p.

The Emergency Department, St John's, 1998, Resident's guide to the state of the Soufrière Hills volcano following the scientific assessment of July 1998 and the dangers of volcanic ash with tips for cleaning up ash. Montserrat, West Indies. August 1998.

Federal Emergency Management Agency (FEMA), 1984, The mitigation of ashfall damage to public facilities: lessons learned from the 1980 eruption of Mount St. Helens, Washington. Region X, Wm. H. Mayer, Regional Director. 1984.

FEMA/USGS, 1999, Volcanic ashfall: How to be prepared for an ashfall. November 1999.

Johnston, D., and Becker, J., 2001, Volcanic ash review - Part 1: impacts on lifelines services and collection/disposal issues: Auckland Regional Council Technical Publication No. 144, 50 p. (http://www.aelg.org.nz/publications.htm#aelg13)

Lauer, S.E., 1995, Pumice and ash, an account of the 1994 Rabaul volcanic eruptions: CPD Resources, Australia, 80 p.

Mt. St. Helens Technical Information Network, 1980, Ash particles and home clean-up problems; advice from the University of Idaho. Bulletin 7. Federal Coordinating Network, May 1980.

Zais, R., 1999, City of Yakima: Presentation on the eruption of Mount St. Helens to Regional Council Civil Defense in New Plymouth, New Zealand.

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