Great concept. It's amusing to think of how this would be done, for real. You could rent a giant to draw with a stencil and fill in the grooves with scoops of snow or, like Christo, you could hire caterpillar tractors and dig the roads out in the shape of the letters or you could simply imagine that a mountain can draw on its own body!
the mountain could draw on its own body,but mother nature always told it that tattoos are not a good choice.but you could ask thousands of yetis to arrange themselves that way or put some message t-shirts on the mountains or ask birds to poop specifically in that area.