I learned somewhere else on this forum that if the pipes are steel their darker color will attract a few degrees of solar warmup and perhaps some transmission of ground heat through the conductive metal will keep the ice from forming around them. Someone showed pictures of it (maybe it was MNFISH)

If they are PVC then it might be helpful to wrap them with black or dark tape (or find a really good plastic primer and paint designed to adhere to plastic/pvc) to help warm them up with the available solar energy.