UPDATED: Oct. 12, 2010 5:29 p.m.

VAIL, Colo. (CBS) – The search for a Chicago hiker who vanished more than a week ago in the Colorado mountains will officially be suspended at midnight Wednesday.

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James Nelson, 31, has been missing since Oct. 3 when he left for a five-day, 25-mile solo trek on the Mount of the Holy Cross near Vail. Nelson is an experienced hiker and belongs to a backpacking club in Chicago, but this was his first trip to this area of Colorado.

The mountain 15 miles southwest of Vail is one of the best known of Colorado’s peaks over 14,000 feet.

Lead by the Eagle County Sheriff’s Office, Vail Mountain Rescue along with five different search and rescue teams worked an excess of 1,000 hours over 4 days, but, despite these efforts they were not able to locate James, according to a release from the sheriff’s office.

“The decision to suspend the search for James was very extremely difficult,” said Eagle County Sheriff Joe Hoy. “Search and rescue teams have scoured all of the terrain that could safely be searched on foot, some of it searched several times, in addition to the extensive aerial search with no results.”

Fifteen search and rescue volunteers looked for Nelson on foot, in areas focused outside of his planned hiking route.

More manpower and air support have been held up due to inclement weather. Denver CBS station KCNC-TV reported that the mountains of Colorado were hit with rain and snow as a potent October cold front blew in.

Stan Bush of KCNC-TV reports that Nelson has the proper gear, but only enough food for five days.

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Nelson’s fiancée reported him missing Friday, after he was supposed to meet up with friends and never showed up. At that point, the woman called police.

Ever since, authorities have been searching the ground and air for Nelson. But there has been no sign of him.

Nelson is a records director for the Chicago-based Evangelical Lutheran Church in America and is known as a friendly, detail-oriented employee, according to John Brooks, a spokesman for the organization.

“A lot of people who work for this organization and who know him … are deeply concerned about him,” Brooks told CBS 2’s Kristyn Hartman. “We certainly hope it all turns out well.”

There are also messages about Nelson on Facebook and at the Chicago Backpackers Meetup Group website. Nelson has taught classes at a Lincoln Park sporting goods store.

Nelson did not have a cell phone with him. He went out completely alone without any knowledge of the terrain.

Experts in the field discourage individuals from searching on their own.

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