Enjoy this collection of Mt St Helens photos portraying the volcano as she appears in 2017. Info and history of the Mount St Helens 1980 volcanic eruption is included below.
Mt St Helens is considered one of the youngest volcanos, its cone having taken shape only 40,000 years ago. Over the last 500 years, according to studies of the mountain’s strata, it has displayed a pattern of erupting and then lying quietly for roughly 120 to 150 years or so before erupting once again, over and over. Between 1857 until 1980, the giant slept, with a few emissions of steam in the midst of that period.
In her most recent glory, she measured approximately 9,600 feet (3,000 m) in height, the 5th tallest mountain in the USA. Through most of the year, her beautifully symmetrical cone was heavily cloked in robes of ice and snow.
On March 20, 1980, the volcano roused herself with an earthquake registering 4.2 on the Richter scale. Over the next days, the mountain quaked with a multitude of small quakes, 174 of them measuring above 2.6. On March 27, it belched ash and steam, the ash column rising to 6,000 feet. A crater took shape and the summit began to fracture.
Through April and early May, steam blasts continued along with 10,000 earthquakes accompanied by ominous groans and palpable shudders inside the volcano. Pressure within the mountain was noticeably disfiguring its north face with a bulge that grew slowly outward and upward.
On May 18 at 8:32am, a 5.1 magnitude earthquake
struck one mile beneath the mountain. Moments later, the unstable bulge gave way and began sliding downhill,
releasing pressure on the forces inside the volcano. The volcano exploded.
The eruption literally blew off the mountain’s north face before shooting sky high, flinging thousands of cubic feet of dirt, rocks, trees, pumice rocks and ash outward and upward. The resulting mushroom cloud topped out at 40 miles wide and 16 miles high. The cloud initially drifted at 60 miles an hour to the east, reaching Idaho in 3.5 hours. The volcano actively erupted for over 9 hours, and then spewed fitfully through the night and over the next several days.
In the blast, Mount St Helens lost the top 1,300 feet (396 m) of her summit. The north side collapse of the mountain “produced the largest landslide-debris avalanche recorded in historic time” (Wiki). The debris avalanche moved at 110 – 155 miles per hour downhill. Most of it funneled into the North Fork of the Toutle River. The resultant debris field covered an area of about 24 square miles approximately 150 feet deep.
After the blast, one headline read: "What a Baby, What a Burp."
In 2004, Mt St Helens began extruding lava into the crater once again, although without the violence that characterized the 1980 eruption. It was considered active until 2008. Since then, the old girl has been remarkably quiet, though the lava dome inside the crater continues to steam.
From the Johnson Ridge Observatory, one can take a 1/2-mile ADA accessible hike to a memorial commemorating the names of the 57 individuals who died in the explosion, including old Harry Truman (not the president) who underestimated the danger and famously refused to leave Spirit Lake Lodge.