Monday, August 13, 2007

Rockfall is a danger Manitou knows all too well

August 6, 2007 - 2:19PM

MANITOU SPRINGS - Rockfall is not just a threat along mountain highways. In this mountain hamlet, 30-ton boulders have made headlines crashing into buildings.

There’s even a monster dangling over a row of houses and the Mason Lodge on El Paso Boulevard, lashed to the mountainside by steel cables.

Marsha Williams is well aware of it. The huge slab tilts at a frightening angle about 200 feet above the house she rents.

“I think about it at times,” Williams said. “But you can’t go through life worrying about that stuff.”

The boulder looks like any of a dozen or so on a ledge above the boulevard. It slipped in 1995 after a heavy rain.

Bruce Brian, who owns the 5 acres adjoining the cliff, recalls the incident, which led authorities to evacuate the home Williams rents, along with three others.

“At the time, people got pretty anxious about it,” Brian said, recalling how 92-year-old Homer Sharpton lived in the Mason Lodge for a time.

“When you’re told you have to leave your house because you might get crushed by a boulder, it creates anxiety,” Brian said.

Mining experts were hired to secure the boulder by lashing it with inch-thick steel cable anchored to bolts drilled deep into adjacent cliffs.

“They engineered it really well,” Brian said. “I’ve been watching it for years. It hasn’t moved since.”

Leonie Theelen and her son, Joe, have lived next door for 20 years. They don’t worry about the lassoed rock as much as the ones around it.

“They only cabled one,” Joe Theelen said. “Look at the others. There’s a hell of a big one up there that didn’t get cabled. Sooner or later, that’s going to go. I can’t think about it.”

Manitou’s public works director, Kelly McMinn, thinks constantly about rockfall.

There are streets in town where he won’t park — such as Lafayette Road and Lovers Lane just off Canon Avenue. He and his crews regularly scoop up chunks of rock that sheer off the cliffs above.

“In 2001, a big rock came off on Lovers Lane and squashed a little red car like a bug,” McMinn said.

“We’ve got a number of rocks we are concerned about. Unfortunately, none of them are on city property. There’s nothing we can do but tell the owners. They usually just shrug their shoulders at us.”

Actually, the city in 2001 bought two houses on Washington Avenue, above Lovers Lane and City Hall, after cracks developed in the street.

“A geologist said the hillside was starting to move toward City Hall,” McMinn said.

Experts said the weight of the two houses was contributing to the slide so the city bought and demolished them. It installed an inclinometer on the hillside to watch for movement.

The most spectacular series of falls may have been 20 years ago, when heavy rains loosed the hillside behind the 900 block of Manitou Avenue, across from the Arcade.

On June 30, 1987, a 6-foot-diameter boulder, estimated at more than 30 tons, rolled down and punched a hole through the wall of Dr. Horace Gardner’s ophthalmology office.

“We were lucky. It ended up a couple inches from the natural gas pipe,” Gardner said.

Days later on July 2, another rock came to rest against a gift shop next door.

Both buildings were evacuated and closed for weeks while miners and a giant crane broke up and removed the rocks and then went to work securing the cliffs behind the buildings with rock bolts.
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