Archives West Finding Aid

Mount St. Helens, located in southwestern Washington State, erupted on May 18, 1980. According to the United States Geological Survey (USGS), the eruption occurred at 8:32 a.m. Pacific Daylight Time. Before the eruption, the elevation of the volcano had been 9,677 feet. Afterward, it was 8,363 feet, having lost 1,314 feet in elevation. The explosion blew out the northwest side of the mountain and pulverized about a third of the volcano, which turned into mud and ash. The ash cloud blackened the sky as it traveled eastward, leaving detectable amounts of ash over an area of 22,000 square miles. The ash cloud reached a height of about 80,000 feet in less than 15 minutes after the eruption. It spread across the U.S. in 3 days and circled the globe in 15 days. In all, 1.4 billion cubic yards of ash were thrown into the air by the eruption of Mount St. Helens.

The first image (1) was produced by the Advanced Very High Resolution Radiometer (AVHHR) aboard the NOAA-6 satellite. The NOAA-6 was a polar-orbiting spacecraft. NOAA-6 holds the record for the longest duration of operations of any polar orbiting meteorological satellite, having been in operation for 2,834 days between its launch on June 27, 1979, and its deactivation on March 31, 1987. It remains in orbit.

The GOES-West satellite, referenced in the rest of the images (2 - 15), was actually GOES-3 at the time of the Mount St. Helens eruption. GOES-3 was the third satellite in the GOES (Geostationary Operational Environmental Satellites) series. The satellites in the GOES series maintain geostationary (fixed position in relation to the surface of the earth) orbits in specific locations. One such position is over the Pacific Ocean, and while occupying that position, a satellite is known as GOES-West. The GOES-West images in this series were produced with the Visible Infrared Spin Scan Radiometer (VISSR) on GOES-3. GOES-3 was launched on June 16, 1978. It remains in orbit and on standby.