Scientists Warn Cascadia Mega-Tsunami Could Flood Pacific Northwest

Scientists warn of a significant risk of a mega-tsunami and catastrophic flooding along the U.S. West Coast due to a potential major earthquake on the Cascadia Subduction Zone, which stretches from Northern Vancouver Island to Cape Mendocino, California. Virginia Tech researchers estimate a 15% chance of a magnitude 8.0 or greater earthquake occurring within the next 50 years, which could cause coastal land to sink up to 6.5 feet and produce tsunami waves up to 1,000 feet tall, threatening millions of residents and cities such as Seattle and Portland. The combined effect of earthquake-driven subsidence and rising sea levels from climate change could increase flood-prone areas from 35 to 116 square miles, putting thousands of people, structures, and roads at risk. Current tsunami preparedness and inundation maps do not account for sea-level rise, potentially underestimating future tsunami impacts. The last major quake on the fault was over 300 years ago, making the event statistically overdue, and the rapid onset of such disasters would leave little time for mitigation or adaptation. The most severe impacts are expected in southern Washington, northern Oregon, and northern California, with Alaska and Hawaii also vulnerable due to their seismic activity.