Strange clouds -- What causes a split sunset?

A picture captured in Oakland Township shows half of the clouds looking like a normal sunset and half looking dark and gray.

This is a rare phenomenon known as a split sunset.

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Sunsets are caused when light scatters as the sun sets below the horizon. After the sun goes below the horizon, it appears to be gone, but it really isn't. Just like we can't see the sun past the horizon, sometimes there are clouds we can't see either.

Sometimes those hidden clouds get in the way of the far-reaching sun rays and create a shadow in the sky. That shadow gets projected, creating a split sunset effect. Everything must line up perfectly for this to happen.