Ash Removal



This section provides a brief overview and should be read in conjunction with detailed cleanup advice found in ICAO Document 9691 Appendix A. Read the Airport Impacts section of this website for additional information about the consequences of ashfall to airports.

Ash accumulation of more than a trace amount requires removal of the ash for airports to resume full operations. Cleaning up airports after an ashfall is a time-consuming, costly, and resource intensive operation. The complexity and immensity of this task should not be underestimated. Ash does not simply disappear (like melting snow) or blow away, but must be disposed of in a manner that prevents it from being remobilized by wind and aircraft and during the cleanup process itself.

Recommended clean up and other mitigation procedures for airports are given in the Manual on Volcanic Ash, Radioactive Material, and Toxic Chemical Clouds published by the International Civil Aviation Organization (ICAO Document 9691). The recommendations are based mainly on experience gained from the various ad hoc measures which have been used by airport authorities during past volcanic eruptions. At-risk airports are recommended to develop comprehensive operational plans for ashfall events. These plans should, where possible, be integrated with airline plans. The ICAO Manual (specifically Appendix A) should be consulted for detailed guidance on the following topics:

  • Standing Pre-Eruption Arrangements
  • From Initial Ashfall Over the Airport To Airport Closure
  • Aircraft Ground-Operating Procedures
  • Aircraft Systems
  • Runways
  • Landing Aids and Traffic Control
  • Ground Support Equipment
  • Computer Systems
  • Radar and Optical Systems
  • Planning for Ash Mitigation

Case study from Mt. Spurr eruption, Alaska 1992

A 3.5-hour-long eruption of Mount Spurr on 18 August 1992 formed an eruption cloud that moved over the Anchorage area and deposited 1-3 mm (1/16-1/4 in) of ash between 8:10 p.m. and 11:00 p.m. The ashfall led to the closure of Anchorage International Airport (AIA), Elmendorf Air Force Base, and Merrill Field. Total cost of removing the ash from the airports, including the cost of protecting and cleaning aircraft caught on the ground is estimated between about $650,000 and $683,000. For more about the effects on the Anchorage-area airports and cleanup operations; see testimonials in a report by Casadevall in 1993.

At AIA, crews found the best technique for removing ash from runways and taxiways involved four steps:
  1. Completely saturate the ash with water in order to 'float it with large quantities of water'.
  2. Sweep the water-saturated ash into windrows or berms using graders and runway sweepers.
  3. Load the ash onto trucks and then hauling the ash to a disposal site at the airport.
  4. Using water trucks, flushing the areas that the graders and runway brooms had swept over. One runway was re-swept and flushed with water more than six times before it was considered safe for use by aircraft.


See Also:
Power Supply > Removal from Insulators