Modeling roadway impacts and recovery from volcanic ashfall from the 2021 St. Vincent eruption.

Ashfall from the April 2021 La Soufrière volcano eruption significantly impacted the Caribbean Island of St. Vincent. Out of all infrastructure sectors, transportation was the most affected across the island, with damages totaling $27.5 million (USD). Removal of ash is a debris management, public health, and disaster concern. This study uses the United States Geological Survey Ash3d model to estimate the thickness of ashfall covering roads, structures, and agricultural lands, totaling 9.4 million ft.³ on roadways, 4.8 million ft.³ on structures, and 147 million ft.³ in agricultural areas. Total ashfall on the island was estimated at 1.3 billion ft.³ Long-term planning and recovery challenges include the remote island location, limited resources, and the existing social and humanitarian needs intensified by the disaster. A staged approach to cleanup, debris management, temporary storage of ash, and sustainable reuse of ash as an aggregate for paving and building materials is proposed. The benefits of new technologies for converting ash into building materials using both off- and on-island systems should be considered for reconstruction materials. Using alternatives to sand mining and developing the adaptive reuse of disaster debris would support long-term recovery and resilience.