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6 <br />and ground rock) typically associated with this type of faulting can be effective paths of <br />groundwater seepage and contribute to slope instability by permitting the creation of <br />zones of elevated pore water pressure. Meteorological Factors <br />We checked climate data for the site vicinity in the office following the site visit. There <br />were no notable rainfall or snow melt events preceding the slope failure. Precipitation <br />for Colorado Springs over the calendar year 2008 and over the previous month has been <br />below normal. Recorded. precipitation (liquid depth) for the preceding calendar month <br />(November 2008) was 0.25 inch in the form of a few light snowfalls. Average <br />precipitation for November is 0.52 inch. Annual precipitation, through the end of <br />November 2008, had been 12.82 inches versus an average of 17.02 inches. <br />Site Observations <br />We observed the slide area from several vantage points on the east, south and <br />southwest sides of the pit. We made observations and took photographs on both <br />December 4 and 5, although the ability to take clear photographs and obtain laser <br />rangefinder measurements of the slide was hampered on the 411, by snowfall and poor <br />visibility. The weather on December 5, 2008, was much improved, which enabled us to <br />obtain better quality photos and a profile of the slide using laser rangefinder <br />measurements on this date. <br />Three views of the slide mass are shown in Photos 2, 3 and 4. The soil filled "hole" was <br />located near the center of the triangular slide mass. The slide mass, based on our laser <br />rangefinder measurements, was about 500 feet high from the pit bottom to the head of <br />the slide mass and about 1,300 to 1,400 feet wide at the base. A vertical to overhanging <br />scarp and partly rubble-filled rift bounded the top of the slide mass. The highest point <br />of the main scarp was about 60 to 80 feet high above the head of the slide mass and this <br />height of scarp extended for abo 500 feet along the southern flank. The scarp then <br />progressively decreased in height both northward and further southward. Based on the <br />width of the rift between the scarp and the head of the slide, the upper portions of the <br />slide mass moved down the slope about 100 to 150 feet. <br />The average slope of the mass of slide materials was about 32 degrees based on a profile <br />developed from the lasesrangefinder. The pre-failure pit slope was probably a <br />maximum of about 40 degrees based on the bench and highwall geometry and the likely <br />maximum repose angle of the soil-like decomposed granite fill. The movement of the <br />slide mass appeared to be predominantly translational, in which the mass moves along <br />a planar surface of rupture and has a relatively shallmv depth, rather than a rotational <br />slide that has a circular or elliptical surface of rupture, although the slide could be a