<img class="styles__noscript__2rw2y" src="https://dsx.weather.com//util/image/w/rad_7356-edit.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0" srcset="https://dsx.weather.com//util/image/w/rad_7356-edit.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 400w, https://dsx.weather.com//util/image/w/rad_7356-edit.jpg?v=ap&w=980&h=551&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 800w" > 1 of 20 Espectro de Brocken observado sobre el Parque Nacional Mount Rainier en Washington (Radka Chapin)

With clouds rolling in and visibility decreasing, Radka Chapin and her fellow hikers decided it was time to end their excursion on the Tamanos Mountain in Washington's Mount Rainier National Park. They were on their way down from the summit when they came across something that stopped them in their tracks: A rare optical illusion known as the Brocken spectre.

"Well, we’re definitely not leaving now!" Chapin wrote in her report on the discussion forum nwhikers.net . "Over the next few hours, the 'spectre' would show for brief moments before it disappeared with moving clouds."

Several hours later, the hikers continued on their way back when they saw the phenomenon again.

"The spectre became more prominent, colorful, and was projected onto clouds directly below us. It was a breathtaking show," said Chapin.

The phenomenon is commonly seen near The Brocken, the highest peak of the Harz mountain range in Northern Germany, hence the name Brocken spectre. The illusion forms when the sun casts a person's shadow in the mountains, and includes a rainbow halo if there are water droplets in the air .

The eerie photos of ghost-like shadows can be seen in the slideshow above.

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