Meteorology: Understanding the Atmosphere            Ackerman and Knox



The geostationary perspective provides frequent viewing, which permits analyzing a time sequence of a volcanic eruption. Volcanic ash can be a significant aviation hazard, so the monitoring of ash plume dispersion using GOES imagery is an important task.

Mt. St. Helens (Location: 46.2N, 122.2W Elevation: 8,363 feet (2,549 m)) erupted on 18 May 1980 and sent thousands of tons of ash into the atmosphere. Below is a GOES 3 view of Mt. St. Helens eruption on May 18, 1980. This is an early satellite instrument and the data quality is sometimes poor.

Below is a sequence of visible imagery taken for the GOES-3 satellite as it observed the Mt. St. Helens eruption on 18 May, 1980. The first image is at 1515UTC and is prior to the eruption. The ash cloud is clearly seen in the next 8 images, spaced one-half hour apart.

What do you notice about the cloud patterns in the vicinity of Mt. St. Helens at the beginning of the eruption?

How does the movement of the ash cloud compare with the movement of clouds?


If you are not sure where the ash cloud is or the bad data, you can test yourself with this Java Applet.