In the years since the cataclysmic eruption of Mount St. Helens, scientific and technological advances in volcanology have enabled new models of volcanic risks and assessment. One such assessment and monitoring model proposed by the USGS, the ‘National Volcano Early Warning System’, contains a very interesting list. It is a categorization and risk assessment of volcanoes in the United States, including these which are classified as the highest threat of them all… The NVEWS is an assessment of the United States volcanoes and their monitoring needs based on the threats posed by the 169 volcanoes which are geologically active
Original source: The Highest Threat Volcanoes in the United States