Close To The Edge is a significant cave

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

 in the Dezaiko Range of the Rocky Mountains

Rocky Mountains

The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 in Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. It is within Close To The Edge Provincial Park and Protected Area

Close To The Edge Provincial Park and Protected Area

Close To The Edge Provincial Park and Protected Area is a provincial park and a protected area in British Columbia, Canada.-History and conservation:...

 about 160km east of Prince George, British Columbia

Prince George, British Columbia

Prince George, with a population of 71,030 , is the largest city in northern British Columbia, Canada, and is known as "BC's Northern Capital"...

.

Cave setting and form

The 20m wide entrance to Close To The Edge is located in a cliff near the summit of an unnamed mountain, but is hidden by a natural rampart and thus only visible from the air. The entrance shaft is 255 m deep, by far the deepest in Canada, and often sports a 20m long overhanging icicle. This is followed by shafts of 32 m, 17 m, 7 m, 10 m, 10 m, 8 m, 9 m, 68 m, and 9 m, ending at a sump

Sump (cave)

Sump is a term used in caving to describe a submerged passage in a cave. A sump may be static, with no inward or outward flow, or active, with continuous through-flow...

. The surveyed

Cave survey

A cave survey is a map of all or part of a cave system, which may be produced to meet differing standards of accuracy depending on the cave conditions and equipment available underground. Cave surveying and cartography, i.e. the creation of an accurate, detailed map, is one of the most common...

 length of all passages only totals 967 metres, while its overall depth of 472 m makes it the third deepest cave in Canada. It is believed that the sump water reappears at Twin Falls Resurgence some 600 m below the entrance.

Exploration

The first recorded entrance sighting was in 1985 by cavers in a helicopter supporting a nearby expedition. The following year the cave was explored to a frozen mud and stone blockage at the base of the second pitch at a depth of 263 m. The blockage was removed in 1994 and exploration continued to a depth of 430m. A final exploration in 2001 discovered the sump at -472 m.

Name

The cave is named for its remarkable cliffside location; a caver standing on the entrance rampart can look down the 255 m entrance shaft on one side and down some 700 metres to the valley floor on the other. This topographic oddity is also reminiscent of the artwork on the 1972 record album Close to the Edge by the band Yes

Yes (band)

Yes are an English rock band who achieved worldwide success with their progressive, art, and symphonic style of rock music. Regarded as one of the pioneers of the progressive genre, Yes are known for their lengthy songs, mystical lyrics, elaborate album art, and live stage sets...

, which featured lakes improbably perched on mountain summits. Local cavers also felt close to the edge of their abilities while exploring the unprecedented deep shaft.