5.4.1 Avalanche Figure A.5 Indicates the Debris Run-Out Areas Which Affect the Town of Alta, and It Indicates Which Structures in Alta Are Vulnerable to Avalanches
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Alta, Utah Hazard Mitigation Plan (2014) Town of Alta Emergency Management Contacts Chris Cawley Mike Morey John Guldner Assistant Town Town of Alta Marshal Town Administrator, [email protected] Administrator Emergency 801-363-5105 [email protected] Manager 801-363-5105 [email protected] 801To access-363-5105 the 2005 Town of Alta General Plan and the official Town Code, please visit www.townofalta.com/gov.shtml# Salt Lake County Multi-Jurisdictional Natural-Hazard Mitigation Plan Annex A Page 2 of 33 Alta, Utah Annex A: Town of Alta 1 Introduction 1.1 Background This document is based in part on existing documents such as the 2009 “WASATCH FRONT NATURAL HAZARDS PRE-DISASTER MITIGATION PLAN,” as well as several documents prepared by Salt Lake County Emergency Management Staff. These documents assist the 16 municipalities and partner agencies within Salt Lake County in reducing the costs of natural disasters by providing comprehensive hazards identification, risk assessment, vulnerability analysis, mitigation strategies, and an implementation schedule. This document reflects elements of the Town of Alta Emergency Operations Plan, regional pre- hazard and emergency management plans and strategies, and mitigation needs and strategies identified in previous hazard mitigation planning exercises. This plan reflects Town of Alta policy as stated in the 2005 Town of Alta General Plan, as well as the Town of Alta, Utah Code. 1.2 Purpose The purpose of this plan is to enumerate hazards which could affect the Town of Alta, describe mitigation strategies for each of those hazards, and provide a framework for revision of hazard mitigation strategies. This document was created by Town of Alta staff with significant guidance from Salt Lake County Emergency Management staff, and it is based on guidelines for local hazard mitigation strategies prescribed by the Federal Emergency Management Agency (FEMA). This plan will be submitted alongside similar documents from other municipalities in Salt Lake County to the State of Utah, which will submit all county documents to FEMA. Completing a pre- hazard mitigation plan allows Salt Lake County as well as local jurisdictions to receive financial disaster assistance from the federal government. 1.3 Scope The Town of Alta Pre-Hazard Mitigation Plan includes identification and assessment of hazards within the Town of Alta’s jurisdiction. This document reflects elements of the Town of Alta Emergency Operations Plan, regional pre-hazard and emergency management plans and strategies, and hazard mitigation needs and strategies identified in previous hazard mitigation planning exercises. Salt Lake County Multi-Jurisdictional Natural-Hazard Mitigation Plan Annex A Page 3 of 33 Alta, Utah 2 Community Profile Figure A.1 Town of Alta within Salt Lake County 2.1 Geography and Environment The Town of Alta is located in the southeastern corner of Salt Lake County, at the top of Little Cottonwood Canyon in the central Wasatch Mountains. The boundaries of this tiny municipality generally traverse the alpine ridgelines at the head of a deep cleft in the Wasatch Front, encompassing 4.1 square miles of rugged mountainous terrain. Alta is most notably home to Alta Ski Area, and much of the land within the Town’s jurisdiction is open space used by the ski area for commercial skiing. The western boundary of Alta is directly east of Snowbird Ski and Summer Resort, in unincorporated Salt Lake County. The highest elevation in the Town of Alta is 11,068’ atop Mt. Baldy, and the center of town is roughly 8600’ above sea level. Climate in Alta is characterized by a long snowy season between November and May, during Salt Lake County Multi-Jurisdictional Natural-Hazard Mitigation Plan Annex A Page 4 of 33 Alta, Utah which time an annual average of 500” of snowfall is measured at 9600’ above sea level. Day-time temperatures during this elongated “winter” season average °__F, and severe storm cycles often persist for several days, featuring heavy snowfall, strong winds, and temperatures near 0°F. Snow cover can linger on upper elevation slopes until August, although the months of June, July, August and September sometimes feature daytime high temperatures approaching 80°F. Summer weather in Alta is generally sunny and mild, although periods of monsoonal thunderstorm activity are not uncommon. 100 90 80 70 Average Max. Temperature (F) 60 Average Min. Temperature (F) 50 Average Total Precipitation (in.) 40 Average Total SnowFall (in.) 30 Average Snow Depth (in.) 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure A.2: Town of Alta Temperature, Precipitation, and Snow Depth Source: "Seasonal Temperature and Precipitation Information". Western Regional Climate Center. Retrieved April 6, 2013. 2.2 Community Facts Alta is known primarily as a recreation destination, as it is home to Alta Ski Area, one of the world’s most iconic winter sports destinations, as well as several privately-owned lodging facilities and several neighborhoods of single-family homes. During a winter season which often lasts from mid-November to early May, deep, natural snow blankets the Town of Alta, turning steep mountain slopes into an economic resource, which supports our local economy and constitutes a major attraction for tourists to visit the State of Utah. During the non-ski season, many businesses in the Town of Alta close for the summer, making Alta a very quiet place. It is during this season, when snowpack recedes and Alta’s vast open landscape bursts with wildflowers, that another important aspect of Alta’s identity is perhaps more apparent: Alta encompasses the headwaters of Little Cottonwood Creek, a vital culinary watershed for the burgeoning population of the Salt Lake Valley. Many businesses in the Town of Alta are not open for service during the non-ski season, and dispersed recreation destinations such as hiking trails to Cecret Lake and Catherine’s Pass, as well as a United States Forest Service Campground in Albion Basin, are primary attractions for locals of Alta and the Salt Lake Valley, as well as tourists. Salt Lake County Multi-Jurisdictional Natural-Hazard Mitigation Plan Annex A Page 5 of 33 Alta, Utah The Town of Alta was formally incorporated in 1970, with municipal services developing throughout the 1970’s and 1980’s. William “Bill” Levitt was mayor of Alta from 1972 to 2006, and today Alta looks much like it did throughout Bill’s service as Mayor. 2.3 Population and Demographics In 2010, the official population for the Town of Alta was 386. During ski season, a few hundred seasonal workers populate employee residences at various businesses throughout Alta, and when the hotels and other lodging business in Alta are at capacity, there may be over one thousand additional persons staying in Alta on a transient basis. Alta Ski Area can host 4500 skiers on a busy day, and can sometimes experience high volumes of summer-time dispersed recreation use, meaning that the number of people present in Alta at any point in time is difficult to estimate, and often far exceeds the official population. Figure A.3: Town of Alta Zoning 2.4 Land Use and Development Land use and development are guided by the 2005 Town of Alta General Plan and the official Town of Alta, Utah Code. The United States Forest Service (USFS) is the primary landowner in Alta, with over 80 percent of land within Alta’s boundaries in public ownership, and Alta Ski Lifts Company is the largest private landowner. Recreation and open space is the primary land use designation in Alta, although there are distinct areas of town, primarily along state highway 210, in which commercial and/or residential uses are permitted. There are three distinct clusters of Salt Lake County Multi-Jurisdictional Natural-Hazard Mitigation Plan Annex A Page 6 of 33 Alta, Utah single family homes in upper Albion Basin, although these homes are not served by the Town of Alta sewer or water systems, and they are accessible only by over-snow vehicles during winter. The Town of Alta supports additional development following our land use ordinances. The only major development currently approved for construction is the 25.16 acre Patsy Marley subdivision, which holds 10 lots zoned for single family residential use. Under current land use and administrative restrictions, Alta can expect the development of 34 single family homes and roughly 140 additional hotel rooms within existing hotel properties. It is possible that Alta Ski Area will pursue expansion of its ski area operations by constructing new ski lifts and altering natural terrain features; such development would constitute a significant change to the Alta landscape and land-use characteristics of any associated open space, and it would be required to conform to Town of Alta zoning regulations. The 2005 Town of Alta General Plan states that future development in the Town of Alta should be focused in the “Commercial Core,” an area which stretches from the Alta Ski Area Albion Base, near the east end of state highway 210, to the Alta Peruvian Lodge, just west of the Alta Ski Area Wildcat Base. 2.5 Data Sources and Limitations Town of Alta staff consulted various sources of information in the preparation of this document, including Salt Lake County; the State of Utah; Wasatch Front Regional Council; FEMA; Utah Department of Transportation; US Census Bureau; The 2005 Town of Alta General Plan; Alta, Utah Town Code; Town of Alta GIS resources; the USFS Utah Avalanche Center, and others. The Town of Alta is a very small municipal organization, with limited financial and human resources to devote to hazard mitigation planning. This document, and the process it represents, reflects collaboration between Town of Alta staff and various Salt Lake County agencies such as SL County Emergency Management and the Unified Fire Authority, as well as input from members of the public.