Injection, transport, and deposition of tephra during event 5 at Redoubt Volcano, 23 March, 2009

► We simulate tephra deposition during event 5 at Redoubt Volcano, 2009. ► Strong wind shear blew the cloud N, W, and E at different elevations. ► Formation of ice aggregates accelerated ash removal from the atmosphere. ► We modeled aggregation by distributing fine ash among coarser size bins.