Computer Terrain Mapping, Inc. 2005 map The Alpine Loop Avalanche Hazard data set shows the risk of avalanche on lands along the Loop. This data set is one of the development constraints used to determine (limit) the Development Potential. One of the most serious dangers to life and property within the Alpine Loop area is the hazard presented by avalanches. The Mountain Studies Institute (Silverton) web site documents that there have been 264 avalanche deaths between 1874 and 1991. A variety of data sources were combined to produce this data set, including mapping from the Colorado Geological Society, Colorado Avalanche Information Center and INSTAAR. The Alpine Loop Spatial Analysis and Mapping Project inventoried natural and cultural resources and identified important areas where overlapping resources occur. The results from this project will provide an opportunity for area stakeholders - landowners, outdoor enthusiasts, surrounding communities, federal government agencies and local and national preservation groups - to come together to find solutions that maintain the Alpine Loop experience for future visitors and residents, while working within the framework of landowner objectives as well as local and federal government goals. The Alpine Loop Spatial Analysis and Mapping Project analyzed the Alpine Loop landscape, considering important natural and cultural resources along with the likelihood of development based upon building constraints. The Project aims to provide a planning tool for area stakeholders as they consider the variety of land management options and the future of this magnificent region. The next logical step will be to craft solutions that work within the framework of landowner desires, local and federal government land management goals, and available financial and technical resources to manage the area in a way that preserves the Alpine Loop experience for future generations. While the Alpine Loop lies within three counties - San Juan, Hinsdale and Ouray - the analytical work extended into a portion of San Miguel County. The resulting mapping and analyses will: 1. Create a spatial foundation to aid future projects in the Alpine Loop corridor; 2. Serve as a prioritization tool for evaluating the conservation potential of individual private parcels; 3. Provide the necessary framework for pursuing future funding opportunities. 2003 2005 Data were retrieved from various sources and analyzed between 2003 and 2005. See Data Quality Information for time information for source data. Complete None Planned -107.8725478 -107.2256611 38.08819806 37.73515861 None Conservation Resources Development Avalanche None United States North America Colorado San Juan Mountains Ouray County San Juan County Hinsdale County San Miguel County Ouray Silverton Lake City None None. Computer Terrain Mapping, Inc. Ed Russell President mailing

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Boulder CO 80306 USA 303.444.1670 303.443.4856 ctm@ctmap.com 8:00-5:00 MT This data set is the product of a collaborative process between numerous agencies, organizations and interested individuals from the beautiful Alpine Loop region. GRASS version 5 on Red-Hat Linux version 8.0 exported to an ASCII Grid Avalanche Hazard was determined from a variety of data sources of unknown accuracy. Most data sources were based on USGS 1:24,000 scale maps. Data are calculated from a variety of data sources of unknown accuracy. Only basic spot checking based on knowledge of terrain was performed. Although every effort was made to find avalanche information for the entire study area, there may be gaps due to lack of data. Dale Atkins, Colorado Avalanche Information Center 20011001 Boulder Colorado Colorado Avalanche Information Center CAIC is an abbreviation for Colorado Avalanche Information Center CDOT is an abbreviation for Colorado Department of Transportation Source is distributed on CD with map images based on USGS 1:24,000 scale maps. CD Map Images 1996 20011001 Start of study and publication date. CAIC Historic avalanche information and hazards. Arthur I. Mears, Colorado Geological Survey 1979 Denver, Colorado Colorado Geological Survey; Department of Natural Resources; State of Colorado Special Publication 7. Based on USGS 1:24,000 scale maps. Paper Atlas 1979 publication date Colorado Avalanche Studies Historic avalanche information and hazards. Rebecca Summer and Margaret Squier 1976 Boulder, Colorado Institute of Arctic and Alpine Research Adopted by San Juan County Commissioners Paper maps 1976 date received INSTAAR Avalanche hazards for San Juan County Betsy R. Armstrong Richard L. Armstrong 1977 Boulder, Colorado University of Colorado Institute of Artic and Alpine Research Occasional Paper 25, 132 p. Based on USGS 1:24,000 scale maps. Paper Atlas 1977 publication date Ouray County Avalanche Atlas Historic Avalanche information for Ouray County Colorado. Leonard Miller Betsy R. Armstrong Richard L. Armstrong 197601 Boulder, Colorado University of Colorado Institute of Artic and Alpine Research Occasional Paper 17, 232 p. Based on USGS 1:24,000 scale maps. Paper Atlas 197601 publication date San Juan County Avalanche Atlas Historic Avalanche information for San Juan County Colorado. Digitize paper and CD image map sources. Categorize avalanche chutes and runout zones. Convert to raster format with values 3 (high restriction of development potential due to avalanche hazard) for avalanche chutes, 2 (medium restriction of development potential due to avalanche hazard) for runout zones, 0 (no restriction of development potential) for areas of no hazard and no data value for areas of unknown hazard. CAIC Colorado Avalanche Studies INSTAAR San Juan County Avalanche Ouray County Avalanche Atlas 2004 Raster Grid Cell 1256 1863 Universal Transverse Mercator 13 .9996 -105 00 00 00 00 00 500000 0 coordinate pair 30.0 30.0 METERS North American Datum of 1983 (NAD83) GRS 1980 6378137 298.257222101 Avalanche hazard grid cell Any of the data elements in the avalanche hazard file author Avalanche hazard grid cell value The value describes the risk of avalanche with values 3 (high restriction of development potential due to avalanche hazard) for avalanche chutes, 2 (medium restriction of development potential due to avalanche hazard) for runout zones, or 0 (no restriction of development potential). author 0 3 Computer Terrain Mapping, Inc. Ed Russell President mailing

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Boulder CO 80306 USA 303.444.1670 303.443.4856 ctm@ctmap.com Alpine Loop Spatial Analysis and Mapping Project Computer Terrain Mapping, Inc. (CTM) provides this data set as is. CTM makes no guarantee or warranty concerning the accuracy of information contained in the data. CTM further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although this data has been processed successfully on computers at CTM, no warranty, expressed or implied, is made by the CTM regarding the use of this data on any other system, nor does the fact of distribution constitute or imply any such warranty. Contact distributor to receive additional copies. 200504 Computer Terrain Mapping, Inc. Ed Russell President mailing

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Boulder CO 80306 USA 303.444.1670 303.443.4856 ctm@ctmap.com 8:00-5:00 MT FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998