First noctilucent 'night shining' clouds of the season grace Washington's summer sky

SEATTLE — The first "night shining" clouds of the season have appeared in the summer sky over Washington state.

These noctilucent clouds are rare and often occur during the summer months. They are higher than any other cloud in the sky and are most visible between 45 degrees north and 80 degrees north latitude in the Northern Hemisphere.

The ice-blue clouds form 50 miles above the ground in a layer of our atmosphere known as the mesosphere.

Resembling ripple-like reflections of water in the high-altitude sky, noctilucent clouds can appear shortly after sunset on clear summer evenings and stay visible after dark because they still are able to reflect sunlight at their great height.

Summer heating lifts moisture to high altitudes, where it freezes upon contact with fine dust particle from incinerated meteors, volcanic eruptions and man-made pollutants.

The resultant ice crystals can make for a mystical sight in the summertime sky.