Volcanic mountains

Volcanic ash meets the Saharan air layer in a unique display above La Palma


Volcanic ash meets the Saharan air layer in a unique display above La Palma

Mother Nature can work in mysterious ways to create a work of art out of something that seems nothing out of the ordinary.

In the case of the Cumbre Vieja volcano on the island of La Palma in the Canary Islands, Spain, a stunning cloud ripple recently formed above it amid the ongoing eruptions.

The Institute of Volcanology (INVOLCAN) observed a increased explosive activity on October 2, and amid the high activity, the Moderate Resolution Imaging Spectroradiometer (MODIS) from NASA’s Terra satellite captured a single image showing a dense plume of ash flowing south just two days later.

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According to the Toulouse Volcanic Ash Advisory Center, the plume rose 3 kilometers into the air in October. 4, creating a danger for nearby aircraft. Even though activity has increased, volcanologists have consistently rated Cumbre Vieja’s volatile state as moderate – scoring a 2 out of 8 on the Volcanic Explosive Index (VEI).

According to NASA’s Earth Observatory, the bull’s eye cloud results from a rising column of superheated ash and gas, known as the eruption column.

Satellite imagery of La Palma volcano

Satellite imagery of La Palma volcano


The floating pillar of water vapor and other gases rose rapidly upward until it collided with a drier, warmer layer of the Saharan Air Layer (SAL) at about 5.3 kilometers above sea level, according to INVOLCAN.

“A handful of incredibly unique ingredients have all come together to create an incredible spectacle on the Spanish island of La Palma as an incredibly active volcano erupted,” said Jessie Uppal, meteorologist at The Weather Network.

Saharan air layer (SAL)

Saharan air layer (SAL)

The unusually warm air at the top of a temperature inversion acted as a cover, preventing the volcanic plume from going higher. As a result, it just leveled off and spread horizontally.

“We know that warm air naturally rises in the atmosphere where cooler air surrounds it. This is exactly how we get thunderstorms to develop, but in this case we have an erupting volcano,” explains Uppal.

The inversion is a layer in the atmosphere that temperatures typically increase with height, Uppal said, and that’s why “we see this column of volcano plume stop there and work its way out.” .

“Since volcanic eruptions usually have natural ebbs and flows in their intensity, the pulses of the upward flow of the volcanic column created concentric gravity waves when they reached the temperature inversion and propagated towards the “outside. The process is similar to how a stone falls into a pond. creates ripples that propagate outwards,” NASA’s Earth Observatory explained.

Temperature inversion

Temperature inversion

The good news about the particular eruption that put on the scenic spectacle was its lack of energy to send large amounts of ash and gas into the stratosphere, NASA said, where it can have “strong and lasting effects on weather and climate “.

Thumbnail courtesy of Daniel Lopez / Storyful.

With files from Jessie Uppal, Meteorologist at MétéoMédia.

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