DRAFT CARBON CO MHMP 1/29/2015 Multi-Hazard Mitigation Plan Carbon County, Wyoming and the Communities of Baggs, Dixon, Elk Mountain, Encampment, Hanna, Medicine Bow, Rawlins, Riverside, Saratoga, Sinclair Little Snake River at Baggs, February 2015 Prepared by: Beck Consulting, Red Lodge, Montana, AMEC Foster Wheeler, Boulder Colorado, and Carbon County Emergency Management DRAFT March 2015 DRAFT CARBON CO MHMP 1/29/2015 Table of Contents Executive Summary………………………………………………………………………………………iii Chapters Chapter I. Introduction ............................................................................................................. I-1 Chapter II. Hazard Identification and Risk Analysis ................................................................ II-1 Chapter III. Dam Failures ........................................................................................................ III-1 Chapter IV. Droughts .............................................................................................................. IV-1 Chapter V. Earthquakes ......................................................................................................... V-1 Chapter VI. Floods .................................................................................................................. VI-1 Chapter VII. Hail ..................................................................................................................... VII-1 Chapter VIII. Hazardous Materials and Waste ....................................................................... VIII-1 Chapter IX. Landslides ........................................................................................................... IX-1 Chapter X. Lightning ............................................................................................................... X-1 Chapter XI. Mine Subsidence ................................................................................................. XI-1 Chapter XII. Snow Avalanches ............................................................................................... XII-1 Chapter XIII. Tornadoes ......................................................................................................... XIII-1 Chapter XIV. Wildland Fires .................................................................................................... XIV-1 Chapter XV. Wind ................................................................................................................... XV-1 Chapter XVI. Windblown Deposits .......................................................................................... XVI-1 Chapter XVII. Winter Storms & Blizzards ................................................................................ XVII-1 Chapter XVIII. Hazard Mitigation Goals and Projects ............................................................. XVIII-1 Chapter XIX. Plan Monitoring, Maintenance, Revision, and Coordination .............................. XIX-1 Appendices Figures Figure 1.1 North Platte River at Saratoga, December 2014 .......................................................... I-1 Figure 1.2 Carbon County Land Ownership Map .......................................................................... I-6 Figure 3.1 Dams in Carbon County ............................................................................................ III-4 Figure 4.1. Wyoming Weekly Drought Severity .......................................................................... IV-2 Figure 4.2 Carbon County Annual Precipitation (1895-2014) ..................................................... IV-3 Figure 4.3. U.S. Drought Monitor, Wyoming (map courtesy of NDMC-UNL). ............................. IV-4 Figure 5.1 Historical Earthquakes in Wyoming, 1871 to 2014 (Carbon County circled in blue) .. V-1 Figure 5.2 Two percent probability of exceedance in 50 years map of peak ground acceleration, Western United States (Carbon County area circled in black) ................................................... V-11 Figure 5.3 500-year probabilistic acceleration map (10% probability of exceedance in 50 years). V- 12 Figure 5.4 1000-year probabilistic acceleration map (5% probability of exceedance in 50 years).V- 13 Figure 5.5 2500-year probabilistic acceleration map (2% probability of exceedance in 50 years).V- 14 Figure 6.1 Carbon County HAZUS Flood Hazards ................................................................... VI-13 Figure 6.2 Carbon County HAZUS Flood Depth ....................................................................... VI-14 Figure 6.3 Carbon County HAZUS Building Loss ..................................................................... VI-15 Figure 9.1. Mapped Landslides in Wyoming .............................................................................. IX-1 Figure 9.2 Wyoming Landslide Classification ............................................................................. IX-3 Figure 9.3 Carbon County Landslide Map ................................................................................ IX-11 i DRAFT CARBON CO MHMP 1/29/2015 Figure 10.1 Average annual lightning flash density for 1998-2000 over Wyoming. ..................... X-1 Each pixel represents 5 km2. Illustration courtesy of Vaisala Inc. ................................................ X-1 Figure 10.2 Lightning Fatalities by State: 2004-2013 ................................................................. X-3 Figure 10.3 Lightning Fatalities Weighted by Population by State: 2003-2014 .......................... X-3 Figure 11.1 Mined-out areas and mine subsidence in Wyoming. Gray areas represent mined-out areas with subsidence. Solid areas represent mined-out areas with no known subsidence. ..... XI-2 Source: 2011 Wyoming Multi-Hazard Mitigation Plan ................................................................. XI-2 Figure 11.2 Mined-out areas and mine subsidence in Wyoming (cont.) ..................................... XI-3 Figure 11.3 Mined-out areas and subsidence near Hanna ......................................................... XI-4 Figure 11.4 Mined-out areas and subsidence near Elmo ........................................................... XI-5 Figure 11.5 Subsidence Problems near Hanna and Elmo .......................................................... XI-6 Figure 12.1 Chart highlighting Wyoming as the fifth most at-risk U.S. state for fatalities from avalanches. Figure adapted from the USDA Forest Service, Utah Avalanche Center. ............. XII-2 Figure 12.2 Wyoming avalanche fatalities by activity (1913-2014). Graph from the Bridger-Teton National Forest Avalanche Center. ............................................................................................ XII-3 Figure 12.3 Wyoming avalanche fatalities by location (1913-2014). Graph from the Bridger-Teton National Forest Avalanche Center. ............................................................................................ XII-4 Figure 12.4 Wyoming avalanche fatalities. Map from the Bridger-Teton National Forest Avalanche Center (Carbon County incidents circled in black). .................................................................... XII-5 Figure 14.1 Carbon County Wildland Fire History (1980-2012) ................................................ XIV-7 Figure 14.2 Carbon County Wildland Fire Base Map with Redzones (Wyoming Wildland – Urban Interface Hazard Assessment) .................................................................................................. XIV-9 Figure 14.3 Carbon County Wildland Fire Critical Hazard Area Building Exposure Values (thousands of dollars) ............................................................................................................. XIV-10 Figure 16.1 Wyoming Windblown Deposits .............................................................................. XVI-1 Figure 16.2 Carbon County Windblown Deposits ..................................................................... XVI-2 Tables Table 1.1 Local Documents Consulted .......................................................................................... I-3 Table 1.2 Populations of Incorporated Communities (2010 Census) ............................................ I-7 Table 2.1 Federal Disaster and Emergency Declarations in Wyoming ........................................ II-4 Table 3.1 High and Significant Hazard Dams in Carbon County ................................................. III-2 Table 3.2 Carbon County Dam Failures ...................................................................................... III-5 Table 4.1 Carbon County’s Recent Worst Multi-Year Droughts* ............................................... IV-3 Table 4.2 Peak Commodity Production Changes from Pre-Drought (1994-1998) to Drought (2000- 2002) ........................................................................................................................................... IV-5 Table 4.3 1999 Production and Inventory Value Impact ............................................................ IV-6 Table 4.4 2000 Production and Inventory Value Impact ............................................................ IV-6 Table 4.5 2001 Production and Inventory Value Impact ............................................................ IV-6 Table 4.6 2002 Production and Inventory Value Impact ............................................................ IV-7 Table 4.7 2003 Production and Inventory Value Impact ............................................................ IV-7 Table