A cloudy haze of volcanic ash is looming over Mount St Helens in Washington State, evoking memories of its notorious 1980 explosion, the deadliest eruption in US history. But fear not, scientific authorities have said that a major upset is not likely and the volcano is calm – truth be told, you’d know if this wasn’t the case.
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The cloud currently hovering over Mount St Helens is the result of strong easterly–southeasterly winds that have kicked up the loose volcanic ash that was sprinkled during the 1980 eruptions. As for the temper of the volcano itself, it’s no more active than usual.
The United States Geological Survey (USGS) released a statement on Tuesday, September 16, saying: “There is no change in Volcano Alert Level or Aviation Color Code at this time. Mount St. Helens remains at normal, background levels of activity.”
Mount St Helens doesn’t generally mess around with light clouds of ash, preferring a more direct approach of blowing its top with explosive force. In past events, when this volcano did stir, it announced itself in no uncertain terms through rumbling earthquakes and steam plumes bursting skyward. None of those signals are present now.
This is what happened in 1980. Starting on March 15, the region was rocked by several minor earthquakes, indicating that something was stirring within. This activity culminated on March 20 and 21 when stronger earthquakes shook the mountainside, disrupting its winter snowfall and triggering avalanches.
By late March, steam began venting from the summit, and a bulge of magma started to deform the mountain’s north flank. Over the next two months, the swelling grew at an alarming rate — up to 1.5 meters (5 feet) per day — as pressure built inside.
All hell broke loose on the morning of May 18, 1980, when a magnitude 5.1 earthquake destabilized the bulging slope. The entire north face of the volcano collapsed in the largest landslide ever recorded, instantly uncorking the pressurized magma and releasing a flurry of superheated gas, rock, and ash.
Before and after shots of the 1980 eruption show how St Helens was blown apart and gutted. In a matter of seconds, it lost around 400 meters (1,300 feet) of elevation, transforming its conical peak into the cratered profile we see today.
Mount St Helens: Before, during, and after the 1980 eruption.
Image credit: USGS (Public Domain)
May 1980 remains the deadliest and most destructive volcanic eruption in US history, killing at least 57 people and countless other animals. It also devastated the surrounding region, flattening its forests and cloaking the landscape with debris. To help rejuvenate the area, gophers were sent to the mountain – and they did an outstanding job.
So yes, when trouble is brewing at Mount St Helens, it tends to make itself known. The USGS is constantly keeping a close watch and their message is clear: for now, the mountain is at normal levels of activity. No rumbling quakes, no swelling flanks, no ominous plumes, just a dusty memento from 1980.
Source Link: An Ominous Haze Lurks Over The Deadliest Volcano In US, But USGS Says A Repeat Of 1980 Isn't Coming
