Alaska Volcano Observatory
ASH3D: Ashfall Forecast for Hypothetical Eruption
- This ashfall graphic is the output of a mathematical model of volcanic ash transport and deposition on the ground (Ash3D, USGS).
- This model shows expected ashfall accumulation (deposit thickness) for actual or hypothetical eruptions.
- AVO produces this graphic when a volcano is restless by assuming a reasonable hypothetical eruption, in order to provide a pre-eruptive forecast of areas likely to be affected. During an eruption, AVO updates the forecast with actual observations (eruption start time and duration, plume height) as they become available.
- Colored contour lines represent points of equal ash thickness on the ground. Small accumulations of ash may occur beyond the "Trace" contour. Actual deposit thickness may vary from the forecast as the modelled points are based on our best estimates. Thickness terms are explained here.
- This graphic does not show ash cloud movement in the atmosphere; please refer to the other graphics for ash cloud forecasts. Click here to return to other models output.
- Report ashfall observations here.
- For more information about ASH3D, see USGS Open-File Report 2013-1122.
- Return to Great Sitkin activity page for more information on its eruptive status.
Page modified: November 27, 2017 11:43
Contact Information: AVO Web Team
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