The passing of 36 years amounts to nearly half a lifetime for humans. It represents a mere microsecond for a volcano, a geologic eyeblink for the subduction zone and magma chambers that keep it alive.
Mount St. Helens blew its top the morning of May 18, 1980. Its imprint will stick with Northwest residents all their lives. The memories of canceled church services and families huddled around radios and TV sets. The photos of mud and ice crashing down the mountain and of that giant ash plume, which still carries Hiroshima-like vividness around these parts. The stories of old Harry Truman and the 56 others killed in the blast.
Meanwhile, the mountain has moved on to preparing for an encore.
Scientists from the US Geological Survey reported recently that St. Helens is still “very much alive,” as evidenced by a series of small earthquakes that “have been steadily increasing since March, reaching nearly 40 located earthquakes per week.”
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But don’t panic; there’s no need to go digging in the garage for your keepsake breathing mask just yet. While the mountain is re-pressurizing, it hasn’t shown telltale bulges or unusual displays of gas venting that would indicate an eruption is imminent – certainly nothing like the warning signs it gave in the month before it exploded in 1980.
But St. Helens’ latest stirrings should lend some heft to this month’s observance of Volcano Preparedness Month in Washington. Residents are encouraged every May to learn about local hazard zones and evacuation routes; ask local and state emergency offices and schools about their evacuation plans; and gather basic emergency supplies at home, as well as establishing a plan to reunite with family members after a separation.
For first-hand education, this is also a great time of year to visit the Johnson Ridge Observatory, located less than six miles from the crater rim.
Pierce County residents should know to take education and preparation very seriously – especially in the Puyallup Valley, where lahar sirens and annual school evacuation drills have become a way of life. The eruption of Mount St. Helens, after all, was like a violent sister issuing an alert about her more hot-tempered sibling nearby.
Mount Rainier, though now sleeping, is regarded as one of the most dangerous volcanoes in the country. That’s largely because it stores more glacial ice than the rest of the Cascade volcanoes combined. Some 150,000 people live atop the detritus of lahars that swept down from Rainier several times in the last 4,000 years. Two years ago, scientists held public meetings where they compared Rainier to Nevado del Ruiz in Colombia, which erupted and unleashed a lahar that buried 23,000 people in 1985.
Local communities can be grateful for advances pioneered by seismologists in recent years. A network of sensors and Global Positioning System tools on Rainier’s upper reaches can detect minor disturbances, such as quakes as small as 0.1-magnitude.
Someday, Mount St. Helens’ sister will again release energy exponentially greater than that, and the South Sound had best be ready.
For information on how to do your part, click here.