Nacreous Clouds Outside

An amazing sight through the window of our mountain cabin, fantastic Nacreous clouds in Tänndalen, Sweden. Officially known as Polar Stratospheric Clouds (PSCs), they occasionally form in polar regions during winter, at high altitudes of 15–25 km above the ground in the stratosphere. They are rare and appear bright with vivid and slowly shifting colors within two hours after sunset or before sunrise.