Newberry Volcano’s ash spread over 5000 km worldwide marks a groundbreaking discovery in volcanic hazard analysis. Researchers from the University of St Andrews dated an eruption from Oregon’s Newberry Volcano approximately 140 years ago, revealing ash particles that traveled thousands of kilometers—far exceeding previous estimates. This finding challenges conventional understanding of volcanic ash dispersion, particularly for smaller eruptions. Using Greenland ice cores, scientists matched geochemical signatures to ash deposits, confirming the eruption occurred in 686 AD. Previously, eruptions were thought to occur only once a decade, but this study shows that even minor events can trigger massive ash clouds, disrupting global infrastructure. The VEI 4 classification highlights the region’s vulnerability, underscoring how small eruptions can cause widespread disruption.