Definition

ASHTAM. A special series NOTAM notifying by means of a specific format change in activity of a volcano, a volcanic eruption and/or volcanic ash cloud that is of significance to aircraft operations.

Source: ICAO Annex 15

Description

The ASHTAM provides information on the status of activity of a volcano when a change in its activity is, or is expected to be of operational significance. In the event of a volcanic eruption producing ash cloud of operational significance, the ASHTAM also provides information on the location, extent, and movement of the ash cloud and the air routes and flight levels affected. The maximum period of validity of ASHTAM is 24 hours. A new ASHTAM must be issued whenever there is a change in the level of alert.

ASHTAM Format and Content