If you live in an area with a large amount of snowfall, a snow guard system would be a wise choice to add onto your copper roof. Snow guards act as a protection from a large quantity of snow sliding off of your roof, otherwise called avalanching, at one time. When this avalanching occurs it can cause significant injury to anyone who may be standing below, and also has the potential for extensive property damage.
Snow tends to melt from the bottom up. So, as the snow melts, a layer of water accumulates that acts like a lubricant and allows the larger shelf of snow up top to quickly barrel down. A snow guard system is a series of tab-like structures that are placed in strategic areas around the edge of the roof. They are placed where snow would be most likely to slide off first. The installation of a guard system can help prevent ice dams forming that could cause structural damage to your home. It can also help protect your rain gutters that are not able to hold a heavy load of snow.
Snow guards come in many different designs and materials, so you should be able to find one that fits whatever style of roof you have. They are typically unobtrusive, but can be part of a decorative motif. They are made in many different plastics and metals, including copper.
A copper snow guard system would be a wonderful accessory and addition to your copper roof.