The U.S. Geological Survey (USGS) Volcano Hazards Program's visualization shows the projected ash cloud for three differently-sized, hypothetical eruptions of Mount St. Helens. The visualizations depict a simulation of the spread of volcanic ash, based on a combination of wind data from the National Oceanic and Atmospheric Administration (NOAA) and volcanologist-derived eruption size parameters.
These ash cloud projections are important for understanding the impacts of a volcanic eruption so that air space can be managed accordingly and communities at risk of ash fall can be warned. The visualization uses colors to represent the expected amount of ash in the atmosphere, with warmer colors representing more ash.
Please note: these models update regularly. The image shown above shows a single model for a hypothetical eruption on May 6th 2017. Please click on the link below for the most up-to-date prediction.
Click here to access the visualization of predicted ash clouds
Source: USGS Volcano Hazards Program