Nevado del Ruiz (Colombia) and Mount Rainier (US) exist a hemisphere apart, but they both project similar hazards for communities downstream. Central to their stories is the development and continued presence of weak and collapse-prone hydrothermally altered rock, and perennial covers of glacier ice and snow. Slopes of both volcanos are mantled by loose rock debris that can be remobilized to initiate lahars. At both volcanoes, five major glaciofluvial rivers flow down narrow valleys to lowland areas that support large human populations. More than a 150,000 persons live in areas at risk of lahars that could emanate from Rainier. Thirty-six years ago, Colombia’s Nevado del Ruiz initiated a lahar that killed an estimated 25,000 people. Today, we’ll examine hazards at both volcanoes; discuss international synergies for risk reduction, progress and challenges, and review some practical lessons learned about community risk reduction.
Carolyn Driedger is a Hydrologist and Outreach Coordinator at the U.S. Geological Survey in Vancouver Washington. Her science career began with research on glaciers and glacier-related hazards principally at Cascade Range volcanoes, and at Columbia Glacier Alaska. Carolyn witnessed the May 18, 1980 catastrophic eruption of Mount St. Helens and participated in the initial news media response. This event set the course for several fascinating projects that crossed science disciplines, and it provided a front-row seat for observation and reflection upon the role of scientists in society. Carolyn learned that scientists must use the same degree of creativity and care with public communication that they use with scientific endeavors. Now, as CVO’s Outreach Coordinator, she works in partnership with public officials, emergency planners, media, park interpreters, and educators to advance the cause of eruption preparedness. Some earlier career choices have informed current work, including several years of teaching in a US public school and private school in Kathmandu Nepal, and working for the National Park Service.
On Sat. Nov. 20, 2021, Doug Clark, Professor of Geology at WWU, Bellingham presented Lidar data and new stratigraphic, lake sediment, and radiocarbon constraints shed new light a long-standing dispute about the timing and nature of the last major events of the Cordilleran ice sheet in the Fraser Lowland. These new data paint a remarkable picture of glacier advances and retreats interleaved with rises and falls of local sea level during the closing phases of the Pleistocene ice age.Following its initial retreat from the Puget Sound, the ice sheet briefly readvanced into the Salish Sea near Bellingham, Washington about 14,500 years ago.Immediately afterwards, the ice retreated north of the International Boundary long enough for forests to establish in deglaciated lowland sites.Then, shortly following this retreat, local relative sea level (RSL) rose rapidly by ~20–30 m (~65-100 ft) about 14,000 yr ago, inundating the U.S. portion of the lowlands up to ~130 m above modern sea level.While RSL was at its highest, the ice sheet readvanced across the border to nearly the same extent as the earlier event.
By about 13,000 yr ago, ice had retreated north of the border, and local RSL had fallen to within ~4 m of modern SL. A layer of possible loess (windblown dust) in sediments in Squalicum Lake suggests the ice sheet readvanced for a third and final time between 13,000 and 11,150 yr ago, constructing a moraine ~8 km south of the border town of Sumas, Washington. A series of unusual channels just beyond this final moraine indicate that the ice sheet experienced a catastrophic outburst flood immediately before the ice sheet stagnated and disappeared.
Mass extinctions in geologic time: Implications for the past, present and future
During the past 400 million years of life, evidence of five mass extinction events have been detected in the fossil record. These events caused world-wide destruction and led to collapse of whole ecosystems, producing profound changes in Earth’s history and forever altered the evolution of life. Mass extinctions constitute one of the grand “unifying themes” of our planet. Study of the strata, rocks and ancient fossils related to these episodes of massive dying are revealing much insight into not only the history of our planet, but also evolution and the directionality of life. Such geologic and paleontologic studies can teach us to better understand, slow and possibly reverse the 6th mass extinction now underway. This lecture was presented via Zoom on Sat. Oct. 9th at 4 pm.
George Stanley is Professor Emeritus and former Director of the University of Montana Paleontology Center. In the Dept. of Geosciences at Montana, he taught and conducted research in paleontology and geology for 35 years. His research has helped clarify mass extinctions, the evolution of reef structures and modern and ancient coral lineages.
He is a Fulbright Fellow and former Geologist and Research Associate at the Smithsonian Institution’s Museum of Natural History, a Fellow of the Geological Society of America, Organization for Tropical Studies, and American Association for the Advancement of Science. He has authored more than 300 professional publications and several books. His research has taken him to western Canada, northern Mexico, the Peruvian Andes, Germany, Austria, New Zealand, Japan and China. Now largely retired, he lives in Port Townsend where he enjoys hiking, nature and playing guitar.