Roger Hanson is creating a huge science project in his backyard by the Mississippi River near Monticello.

Last month, he set up a line of 10-foot-high rebar poles with bars across the top and a robotic sprayer to shower them with tons of water 24 hours a day. Now he has a three-story pile of ice about 100 feet long that causes people to stop and stare. He even strung Christmas lights on it, but the ice snapped the cords. "It's incredible. We look at it every night from our back window," said Diana Maxwell .

Hanson's wife, Linda, a school librarian, suggested making a Loch Ness-style dragon. But it morphed into a mini-glacier whose light blue hues twinkled in the sunlight in Big Lake Township Thursday morning.

"Some people like to climb mountains," said Hanson, 58. "I built a mountain."

Hanson is a self-employed programmer who creates stock-tracking software for private investors. He calls himself an armchair engineer. That is evident in his scientific approach to the ice structure by the river.

The river is where Hanson normally pipes thousands of gallons of waste water from his geothermal system. It heats and cools the couple's house, which has big picture windows looking out on his ice work.

Why does he build ice castles?

The geothermal system provides "endless water," Hanson said. "We live in Minnesota and it's cold here. It's something to do in the winter."

He began his back-yard experiment last winter with a tree stump and branches, which snapped from the ice. He discovered that half-inch-thick steel rebar worked a lot better. He soon tired of redirecting his sprayer every half-hour and hooked it to a fishing line extending to the patio door.

The first ice sculpture was two stories high, and took until Memorial Day to disappear.

"Last summer I wanted to see how much flooding we'd get," Hanson said. "It wasn't bad."

He found that once the firm ground, rich with sand and gravel, thawed, it drained the melting ice quickly.

Last year's creation took about 300 tons of water, he estimates. This year he expects to freeze about 2,000 tons of ice.

After his bottom row of 11 rebar poles froze into a solid figure, Hanson climbed a ladder anchored in the base ice. He used a drill and blowtorch to make holes in the top ice to insert a rebar pole frame for the next tier. After inserting five rebar poles for the third tier, "I am at max height," he said.

Hanson has refined his sprayer, which now rotates in an arc from atop a 24-foot flagpole. A wire runs down the pole back to Hanson's office. This year, he controls the spray from his laptop, adjusting spray angle and duration for temperature, wind direction and speed.

But this week the sprayer took a detour and smeared ice across his office window.

His next upgrade will be adding a mini-weather station to his flagpole sprayer box, to gather more precise temperature and wind data.

"I love solving problems," Hanson said. "This here is a great deal of problems. There is a lot of science behind it."

Neighbor Nancy Wolesky said the last time she walked by, she admired the beautiful glacier blue. "I thought of it as ice sculpture."

Jim Adams • 612-673-7658

To see more photos on Roger Hanson's website, go to and click on "The Picture Gallery 2009.''

To see more photos on Roger Hanson's website, go to and click on "The Picture Gallery 2009.''