Most of us living in the upper reaches of North America are getting pretty tired of winter by now, but for one Minnesota resident, the arrival of spring will mean the destruction of his incredible work of art. Software engineer Roger Hanson uses water from his home's geothermal heating system, along with a half-inch rebar framing system and a computer-controlled robotic sprayer, to create gigantic free-form ice sculptures in his backyard. His current masterpiece is 85 feet (26 meters) wide and 64 feet (19.5 meters) tall – although winter's not over yet.

Hanson's geothermal system takes water from the ground at a temperature of approximately 47F (8C) and extracts heat from it for heating his house, cooling the water by about 10 degrees in the process. That cooler, "used" water is then pumped out into an adjacent river ... or at least, it used to be. Since the winter of 2007, Hanson has instead been spraying it over an arrangement of multiple tiered frames and poles on his property, to create his sculptures.

The sprayer is moved by two joined antenna rotators, which control both its elevation and azimuth movements. The rotators are in turn controlled by a software program that Hanson created himself. That program also regularly accesses a weather station on top of the house, adjusting the sprayer's movements based on factors such as wind speed and direction.

To keep the water lines from freezing, a bypass system keeps water trickling through at one-twentieth the flow when the home's heating system isn't running.

All in all, it's a pretty clever way of making do with cold Midwestern winters.

All photos courtesy Roger Hanson

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