Light Effects

We were in Tabon, last week, in the south of Palawan, where the sunsets are amazing. But this, I have to say, I have never seen.

These flattened cones, in a very intense blue, like rays of a cartoon sun in negative, appeared from behind the islands in the bay, and scattered across the sky in an arc with the setting sun. Our host, who’s lived there for almost 30 years, was none the wiser either, but definite that it couldn’t be a light show.

Does anyone know what causes this? Is it some sort of rainbow?