Annual probability of accumulation of ten or more centimeters (four or more inches) of tephra in Washington and Oregon from eruptions throughout the Cascade Range.
Cascades Range (regional, USA only), United States, 1995
Figure 3 in: Wolfe, E.W. & Pierson, T.C. (1995). Volcanic-Hazard Zonation for Mount St. Helens, Washington, 1995. U.S. Geological Survey, Open-File Report 95-497, 12 p., 1 plate. https://doi.org/10.3133/ofr95497
This map was produced by an official agency, but may not be the most recent, most complete, or main operational map.
For the current operational hazard map, please consult the proper institutional authorities.

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Wolfe, E.W. and Pierson, T.C. (1995). Volcanic-Hazard Zonation for Mount St. Helens, Washington, 1995. U.S. Geological Survey, Open-File Report 95-497, 12 p., 1 plate. https://doi.org/10.3133/ofr95497Map Set
https://doi.org/10.3133/ofr95497
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