Mapping Patterns In Ice

I shot this image along a stream at Jefferson Memorial Forest, about a 30-minute drive from my house. This is a 185-second long exposure showing the stream flowing under ice and over a bed of slate. I used a Hoya NDx400 filter to capture the flowing water over the slate. I cropped the image in camera and edited using Lightroom, OnOne PhotoTools and Photoshop. ISO 200; 82mm; f/22; 185 seconds