Volcanic cloud evolution: Characteristics, observational capabilities and challenges

Volcanic clouds composed of solid particles, volcanic gases, and related aerosols evolve from the time of eruption until the cloud constituents are removed from the atmosphere. While airborne, they have the potential to cause damage to aircraft, ranging from acute encounters that can lead to an immediate hazard to flight safety, to chronic wear on aircraft components, to benign encounters where no observable impacts occur. We highlight the evolution of cloud properties through three stages: Stage 1 (recent), through Stage 2 (intermediate), to Stage 3 (final) and comment on the current observational capabilities and challenges of detection and characterization of volcanic clouds.