Hail formation triggers rapid ash aggregation in volcanic plumes

Nature Communications
By: , and 

Metrics

66
Crossref references
Web analytics dashboard Metrics definitions

Links

Abstract

During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-characterized ‘wet’ eruption. The 2009 eruption of Redoubt Volcano in Alaska incorporated water from the surface (in this case, a glacier), which is a common occurrence during explosive volcanism worldwide. Observations from C-band weather radar, fall deposits, and numerical modeling demonstrate that volcanic hail formed rapidly in the eruption plume, leading to mixed-phase aggregation of ~95% of the fine ash and stripping much of the cloud out of the atmosphere within 30 minutes. Based on these findings, we propose a mechanism of hail-like aggregation that contributes to the anomalously rapid fallout of fine ash and the occurrence of concentrically-layered aggregates in volcanic deposits.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Hail formation triggers rapid ash aggregation in volcanic plumes
Series title Nature Communications
DOI 10.1038/ncomms8860
Volume 6
Publication Date August 03, 2015
Year Published 2015
Language English
Publisher Nature Publishing Group
Contributing office(s) Volcano Science Center
Country United States
State Alaska
Other Geospatial Redoubt Volcano
Online Only (Y/N) N
Additional Online Files (Y/N) N
Additional publication details