Future Eruptions at Glacier Peak
Some people have called Glacier Peak the Pinatubo of the Cascades; its eruptions tend to be big and explosive, which has happened a couple of times in the past 12,000 years. The volcano's eruptive episodes are typically separated by several hundred to a few thousand years. Thus in any given year, the probability of a new episode beginning is roughly one in a thousand. Glacier Peak may not erupt within our lifetimes, but if it does its geographic impact would vary depending on the size of the eruption, wind direction, and type of hazards produced. All streams that drain Glacier Peak ultimately flow into the Sauk and Skagit Rivers; thus all lahars and post-eruption sediment would likely affect the growing communities on the these rivers as far as the Puget Lowland.
Future eruptions from Glacier Peak will very likely be preceded by earthquakes, and possibly by measurable swelling of the volcano and emission of volcanic gases. All of these signals could be detected by monitoring equipment operated by the USGS and the Pacific Northwest Seismic Network (PNSN) as long adequate sensor networks are in place ahead of time. The USGS also works with Federal, State, Provincial, and local agencies to prepare for disruption that might accompany renewed activity. A coalition of these agencies, known as the Mount Baker-Glacier Peak Facilitating Committee, has drafted a plan outlining how agencies will work together at the first sign of unrest at Mount Baker or Glacier Peak. If Glacier Peak were to reawaken, the USGS would rapidly deploy additional monitoring instruments and, together with these agencies, establish a local volcano observatory and command center that would keep nearby communities informed of developments.