This roughened cloud feature known as an arcus churned ahead of a powerful storm over Woodlandville, Missouri, US, as shown in the inset radar map. At first glance, the image appears to be in basic black-and-white, but if you look more closely, you might notice the strange light of the trees, making them appear almost frosted. Human eyes can only see light in a narrow range of ‘visible’ wavelengths in the spectrum of electromagnetic radiation. What are we Earth-dwellers to do with the light we cannot see?

Dave Lochhaas (Member 45,937) captures clouds using near-infrared cameras. Unlike ‘normal’ photographs that record the visible light spectrum, near-infrared photography records wavelengths just beyond those that humans can see. ‘What I see through the camera is a different world than what I see with my eyes,’ says Dave. ‘The density of water in the air is much more clearly defined, while a clear sky will show black.’ An arcus, also known as a shelf cloud, is a ridge of cloud that juts out at the front base of an advancing storm. It is a harbinger of imminent heavy showers. Even more than in the visible spectrum, the lights and darks of Dave’s arcus mirrored the drama of the powerful storm that was soon to arrive.