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The sky is broken!

You don’t have to fall into a volcano or be engulfed in molten lava to experience its dangers.

A volcano’s ash plume can be as dangerous as a sky full of razor blades.

Photo from the air of thick, light gray, billowing clouds of volcanic ash.

Ash plume of the Eyjafjallajokull Glacier volcano in Iceland in April 2010.

The recent eruption of the Eyjafjallajokull Glacier volcano in Iceland has sent ash plumes into the atmosphere. When the plume has drifted over the United Kingdom and Europe, airline flights have been be cancelled.

Why?

Person's hands holding a pile of very powdery, gray volcanic ash.

Volcanic ash can be as fine as baby powder.

Jet engines on airplanes don’t like ash any more than your lungs do. The powdery ashes are like tiny shards of broken glass. The particles are very sharp, rough and abrasive to any surface they encounter, especially at high speed. Jet engine turbine blades are definitely in that category.

Particles are rough, with sharp edges and holes. Scale measurements show that particles are about 100 micrometers across.

Scanning electron microscope images of volcanic ash particles. Credit: (left) Pavel Izbekov and Jill Shipman, Alaska Volcano Observatory / University of Alaska Fairbanks, Geophysical Institute. (right) U.S. Geological Survey.

Besides the abrasion problem, the inside of the jet engine is hot enough to melt the glassy particles, clogging up parts of the engine. Flying through a thick plume of volcanic ash is a sure way to shut down a jet engine pronto.

Much better, in this case, to keep the planes on the ground—or figure out exactly where the plume is and avoid it. Even if a plume is too thin and spread out to see, it could still have enough ash particles to pose a hazard.

So how can airplane operators find the plume so they know where to not send the planes?

Like clouds, the ash plume moves with the wind currents. Weather forecasters have computer models to help predict where the plume will go next. But they still need to be able to monitor it and make sure it is really going where the computers say it is going. They also need to be able to evaluate how thick and dangerous the plume really is.

Map shows shadowed area extending from Iceland volcano and covering much of the United Kingdom and Europe.

Map of the extent of the plume from the Iceland volcano. Map was made from computer model results.

The GOES satellites gather images at different wavelengths of light that can be processed to show where the ash plume is. However, the image doesn’t really say much about the particle concentrations or sizes, important information for aviation.

Four images, showing cloud features in shades of gray. Lower right-hand image shows a black area.

Example of current GOES Volcanic Ash Imagery product. This product was created from GOES data, and processed to compare images in different wavelengths of light. Airborne volcanic ash (when present) shows as dark shades in the lower-right panel. Other panels show various cloud features.

Currently, the Advanced Satellite Products Branch and the Cooperative Institute for Meteorological Satellite studies at the University of Wisconsin at Madison as well as the Cooperative Institute for Research in the Atmosphere (CIRA) in Fort Collins, Colorado, together with the NOAA/NESDIS RAMM Branch develops and distributes the volcanic ash data products.

The new GOES-R Advanced Baseline Imager will do a much better job of gathering data from more different wavelengths of light so that a much more detailed picture of the ash plume can be made, including its extent, height, mass, and particle size. This information will also be used to further develop those computer models that predict where the ash plume will go and where the ash will fall.

The GOES-R will give aviators the information they need to fly through or around the plume safely, and those on the ground advance warning of when to go inside and hold their breath!