Nacreous Clouds Adorn Húsavík Sky

Friday afternoon, nacreous clouds adorned the sky above the town Húsavík, North Iceland, mbl.is reports. Luckily, Hafþór Hreiðarsson caught a picture of the rare, colorful phenomenon in the sky above Opal and Donna Wood — two schooners, docked in Húsavík harbor, which are part of the North Sailing fleet, used for sailing expeditions in Iceland and Greenland.

Nacreous clouds (also called mother-of-pearl clouds, since ‘nacre’ means mother-of-pearl) are very high clouds that form in the lower stratosphere over polar regions when the sun is just below the horizon — either after sunset or before sunrise. They are illuminated from below and often glow in vivid colors.

The ice particles that form nacreous clouds are much smaller than those that form more common clouds. These smaller particles scatter light in a different way, creating the distinctive luminescent appearance. They are most likely to form in very cold and dry weather.

Due to their high altitude and the curvature of the Earth’s surface, nacreous clouds are lit up by sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn and after dusk. They are most likely to be seen in places with higher latitudes.

You can read more about nacreous clouds here.