A Shelter Comes out the Hahn Cabin Entrapment and Fire Shelter Deployment

Total Page:16

File Type:pdf, Size:1020Kb

A Shelter Comes out the Hahn Cabin Entrapment and Fire Shelter Deployment A Shelter Comes Out The Hahn Cabin Entrapment and Fire Shelter Deployment Rice Ridge Fire Facilitated Learning Analysis September 12, 2017 This photo was taken from the gravel bar on Youngs Creek on the afternoon of Sept. 12, 2017, by one of the two firefighters who used this gravel bar as a safety zone when the approaching Rice Ridge Fire surrounded and engulfed them with embers and smoke. 0 Contents 1. Summary………………………………………………………………………………………………. 2 2. Narrative………………………………………………………………………………………………. 3 3. Discussion Points A. Safety Zone……………………………………………………………………………… 12 B. Deploying the Fire Shelter………………………………………………………… 12 C. Lookout(s)……………………………………………………………………………….. 13 D. Structure Protection Plan………………………………………………………… 13 E. The Big Picture………………………………………………………………………….. 14 F. The Safety “Margin”………………………………………………………………….. 14 G. Roles/Responsibilities, Delegation and Communication…………… 17 4. Timeline………………………………………………………………………………………………… 18 5. Conclusion…………………………………………………………………………………………….. 19 6. FLA Team Members……………………………………………………………………………..… 19 7. Appendix – Photos of Fire Shelter After Deployment…………………………….. 20 1 National Wildfire Coordinating Group Definitions Entrapment – A situation where personnel are unexpectedly caught in a fire behavior-related, life- threatening position where planned Escape Routes or Safety Zones are absent, inadequate, or compromised. An entrapment may or may not include deployment of a fire shelter for its intended purpose. These situations may or may not result in injury. They include “near misses.” Fire Shelter Deployment – Removing a fire shelter from its case and unfolding it to use as protection against heat, smoke, and burning embers. 1. Summary Two Spotted Bear Ranger District firefighters on the Flathead National Forest were flown into the Bob Marshall Wilderness to implement a Point/Zone Protection Strategy for the Forest’s historic Hahn Cabin, located within the northern portion of the Rice Ridge Fire. This was the second consecutive Point/Zone Protection assignment for this pair of firefighters. Because of concerning bear activity during the first assignment the firefighters requested extraction and reassignment. Hahn Cabin is one of several administrative and historic cabins situated along the trail system of the Bob Marshall Wilderness Area in Montana. The objective of the two firefighters was to monitor the progression of the Rice Ridge Fire toward the cabin and, as conditions necessitated, protect the historic structure with a sprinkler system, protective wrap and/or firing out around the building. The sprinklers and other water handling equipment, along with structure protection wrap, had all been installed weeks prior to the firefighters’ arrival on the afternoon of September 11, 2017. Winds and Fire Activity Increases The next day, on the afternoon of September 12, the Rice Ridge Fire advanced north and east under Red Flag conditions, with humidity in the low teens and ridgetop winds gusting 25-35 mph. The two firefighters had spent the morning completing projects around the cabin and monitoring the approaching fire’s progression, as well as the fire’s progress toward the nearby occupied Jumbo Mountain Lookout, located 2.5 miles east of the Hahn Cabin. During the latter afternoon into the early evening, the firefighters noticed that both the winds and fire activity were increasing. They had traveled to a gravel bar on Youngs Creek (that they had previously identified as their Safety Zone), located approximately 0.5 miles (a 7-minute walk) north of the Hahn Cabin. From this location, they observed some canopy fire to the south of the Hahn Cabin and black smoke near the cabin. The firefighters returned to the cabin to start the pumps, close-up doors and windows, and burn-out—readying the cabin for the imminent fire impact. Next, as they had previously discussed, the two firefighters separately and independently made a hasty retreat back to that gravel bar on Youngs Creek—their predetermined Safety Zone. 2 Entrapment and Fire Shelter Deployment Site While the fire continued to actively burn adjacent to what they had previously agreed to and considered a Safety Zone, this gravel bar would become an entrapment site as well as a fire shelter deployment site. The two firefighters deployed a single fire shelter to prevent injuries such as burns from ember wash and/or smoke inhalation. Although they had two fire shelters, the two firefighters both took refuge under one shelter. As they had originally planned, the two firefighters spent the night on the gravel bar with the fire continuing to burn around the cabin and their location. On September 12, the day of their entrapment and shelter deployment, the Rice Ridge Fire grew nearly 16,500 acres. The next morning, the two firefighters returned to the undamaged cabin and began to mop-up around the cabin and remove the water handling equipment. The two firefighters then began their three-day 48-mile trek to the Meadow Creek Trailhead via Big Prairie Work Center and Black Bear Cabin. Rain and snow was observed at Hahn Cabin on September 13 and 14. On September 14, the nearby Big Prairie RAWS logged precipitation for the first time over 30 days. A Facilitated Learning Analysis (FLA) Team was ordered on September 22. The FLA process was adopted by the U.S. Forest Service in part to reduce stigmatization around reporting close calls and to identify systemic issues in the way our firefighting professionals are trained to make decisions. Stigmas tend to exist around recognizing and vocalizing the presence of an unacceptable risk, being entrapped, or using the full range of tactics and tools provided to us, including our fire shelters. 2. Narrative “This was a normal operation for us here on The Bob,” informed a fire management employee who works for one of the Forests that administers the Bob Marshall Wilderness Complex. The 1.5 million-acre Bob Marshall Wilderness Complex, often referred to as “The Bob,” is comprised of the Great Bear Wilderness, the Bob Marshall Wilderness, and the Scapegoat Wilderness. Managed by four National Forests and five Ranger Districts, it represents the Lower 48 States’ third largest wilderness complex. The northern edge of the Rice Ridge Fire, which started on July 24, 2017, located outside of the wilderness would merge with the Reef Fire within the boundary of the Bob Marshall Wilderness Complex on September 7. 3 The Rice Ridge Fire was being managed by a Type 1 Incident Management Team (IMT1). When this fire merged with the Reef Fire, the management of these two fires was also merged under the IMT1. In addition, the IMT1 was also managing the nearby Liberty Fire and was in discussions regarding assuming control of the Type 2 Park Fire, as well as managing a new fire start at the extreme east end of the Rice Ridge Fire. National Wildfire Coordinating Group Definition Point/Zone Protection – A wildfire response strategy which protects specific assets or highly valued resources from the wildfire without directly halting the continued spread of the wildfire. Definition Extension – 1) Points or Zones being protected may be communities, individual structures, areas of high resource value, etc. 2) Continued wildfire spread may be desirable in order to achieve management objectives or may be inevitable due to extreme burning conditions, safety concerns, or other limitations. Other wildfire response strategies are: Monitoring, Confine, Contained, and Suppression. Local Unit to Manage the Rice Ridge Fire A discussion occurred between the District Duty Officer and the IMT1 Operations Section Chief regarding the recently merged Reef Fire. It was decided that given the amount of activity on other portions of the Rice Ridge Fire and the knowledge and capabilities of the local unit, the values and tactical operations within the Bob Marshall Wilderness Complex would be managed by the local unit. The northern edge of the Rice Ridge Fire that was actively burning in the Bob Marshall Wilderness Complex was being managed with a Point/Zone Protection Strategy (see definition above). Wildland fires are a naturally occurring disturbance in the Bob Marshall Wilderness Complex ecosystems. An objective of the wildland fire program is to allow fire to perform its natural role in the evolution and maintenance of these wilderness ecosystems. The fire suppression strategy that was selected would provide Point Protection at several historic administrative cabins dotted within the Bob Marshall Wilderness Complex, including the Hahn Cabin and the Jumbo Mountain Lookout. It was determined that these two structures were the primary infrastructure values within the fire area that could likely be impacted by wildfire. The area of the Bob Marshall Wilderness Complex where these two values are located is remote. Hahn Cabin is nested in the Youngs Creek drainage of the South Fork of the Flathead River, with Jumbo Mountain Lookout perched 2.5 miles to the east. Hahn Cabin is approximately 18 miles from the nearest trailhead. However, this trailhead route was impacted by wildfire and therefore had restricted access. Fire personnel would therefore be inserted via helicopter to implement Point Protection for Hahn Cabin, including wrapping the cabin and outbuildings with structure protection wrap and establishing a gravity feed water handling/sprinkler system and pump/sprinkler system for the structures. The local District had a structure protection plan and structure wrapping supplies cached at the Ranger District. Safety Zone Location Identified
Recommended publications
  • Access Amendment 60 Day
    317 E. Spruce Street PO Box 7274 Missoula MT 59807 406 544-9863 [email protected] October 3, 2019 Secretary, U.S. Department of Agriculture 1400 Independence Ave, SW Washington, D.C. 20250-0003 Chief, U.S. Forest Service 201 14th Street, SW Washington D.C. 20250 Secretary, U.S. Department of the Interior 1849 C Street, NW Washington, DC 20240 Director, U.S. Fish and Wildlife Service 1849 C Street, NW Washington, DC 20240 RE: 60-Day Notice of Intent to Sue under the Endangered Species Act- Idaho Panhandle National Forest, Kootenai National Forest and the Lolo National Forest You are hereby notified Alliance for the Wild Rockies, and Native Ecosystems Council (collectively Alliance) intend to file a citizen suit pursuant to the citizen suit provision of the Endangered Species Act (ESA), 16 U.S.C. § 1540(g) for violations of the ESA, 16 U.S.C. § 1531 et seq. Alliance will file the suit after the 60 day period has run unless the violations described in this notice are remedied. The names, addresses, and phone numbers of the organizations giving notice of intent to sue are as follows: Michael Garrity, Executive Director Alliance for the Wild Rockies P.O. Box 505 Helena, Montana 59624 Tel: (406) 459-5936 Dr. Sara Jane Johnson, Executive Director Native Ecosystems Council P.O. Box 125 Willow Creek, MT 59760 Tel: (406) 285-3611 The names, addresses, and phone numbers of counsel for the notifier are as follows: Kristine M. Akland, Attorney at Law Akland Law Firm, PLLC P.O. Box 7472 Missoula, MT 59807 Tel: (406) 544-9863 NOTICE OF LEGAL VIOLATION THE AGENCIES MUST COMPLETE ESA CONSULTATION FOR THE 2011 ACCESS AMENDMENTS PRIOR TO IMPLEMENTING TIMBER SALES IN THE IDAHO PANHANDLE, KOOTENAI AND LOLO NATIONAL FORESTS In November 2011, the Forest Service amended the Forest Plans of the Kootenai, Idaho Panhandle and Lolo National Forests to include wheeled motorized vehicle access and security standards.
    [Show full text]
  • Oberti Resort Design Case Study
    Oberti Resort Design Case Study by Phil Bamber, Kelly Chow, Jessica Lortie & Tanay Wood 1 OBERTI RESORT DESIGN: A SLIPPERY SLOPE Oberto Oberti, founder of Oberti Resort Design, is in first stages of designing a unique resort concept to add to his record. Oberti is determined to be at the forefront of the next innovative project in British Columbia by developing a new ski hill and resort in North America. The resort will operate during the summer months in order to cater to skiers and snowboarders year round. Oberti’s perplexing vision encompasses a unique mountain experience that will increase Oberti Resort Design’s market share of the ski resort industry. However, the implementation of a new ski resort is tricky due to the large project scope and implementation costs. The timing of opening the ski resort and the location of the resort will be critical to the success of the resort. Now, with financing from Japanese investors, Oberti needs to decide which direction to steer the project in to maximize the success of the new ski resort and adhere to its shareholders. This extraordinary mountain experience plans to attract 180,000 ski visits in the first year of operations, whilst maintaining a stable financial position. OBERTI RESORT DESIGN & PHEDIAS GROUP: BACKGROUND After growing up in Northern Italy within close proximity to the Alps, mountains have been a constant source of inspiration in Oberto Oberti’s life.1 Oberti’s personal mountain endeavours have stimulated curiosity and enriched his design concepts. He first started out as an architect and later established Oberti Resort Design in 2005.
    [Show full text]
  • Dr. Robert D. Lawrence the Thesis Area Is Located in the Western Foothills of the North Three Major Rock Units Are Present and T
    AN ABSTRACT OF THE THESIS OF David Allen Jenne for the degree of Master of Science in Geology presented on March 15,1978 Title:STRUCTURAL GEOLOGY AND METAMORPHIC PETROLOGY OF THE GOLD MOUNTAIN AREA SNOHOMISH COUNTY WASHINGTON d' Abstract approved: Signature redacted for privacy. Dr. Robert D. Lawrence The thesis area is located in the western foothills of the North Cascade Mountains immediately east of Darrington, Washington. Three major rock units are present and these include, from west to east, the Darrington Phyllite, a sedimentary m1ange unit, and the Shuksan Schist.Each of these units is bounded by major faults.In the present thesis only the Darrington Phyllite and the melange unit were studied in detail. The Darrington Phyllite consists of phyllitic metapelites with very local interbedded graywacke, conglomerate, and greenschist. The phyllites contain alternating layers of quartz-albite and musco- vite-graphite.In some rocks, this compositional layering is equiva- lent to sedimentary bedding.However, in most locations,it has resulted from metamorphic processes involving the transposition of bedding and metamorphic differentiation during mimetic recrystal- lization. Greenschist is present as tectonically emplaced blocks and as very local interbeds in the phyllite.Along the western margin of the thesis area, greenschist and meta-igneous rocks have been faulted into place.These rocks probably are part of the Jumbo Mountain Complex. The interbedded greenschists contain lawsonite that has been altered to chlorite.This suggests that blueschist.-facies meta- morphism was followed by a temperature increase and greenschist- facies metamorphism. The mlange unit consists of blocks of sedimentary, meta- igneous, and metamorphic rocks in tectonic contact with a sheared pelitic matrix.
    [Show full text]
  • USGS Geologic Investigation Series I-2592, Pamphlet
    GEOLOGIC MAP OF THE SAUK RIVER 30- BY 60-MINUTE QUADRANGLE, WASHINGTON By R.W. Tabor, D.B. Booth, J.A. Vance, and A.B. Ford But lower, in every dip and valley, the forest is dense, of trees crowded and hugely grown, impassable with undergrowth as toughly woven as a fisherman’s net. Here and there, unnoticed until you stumble across them, are crags and bouldered screes of rock thickly clothed with thorn and creeper, invisible and deadly as a wolf trap.1 The Hollow Hills by Mary Stewart, 1973 INTRODUCTION AND Ortenburger for office and laboratory services. R.W. Tabor ACKNOWLEDGMENTS prepared the digital version of this map with considerable help from Kris Alvarez, Kathleen Duggan, Tracy Felger, Eric When Russell (1900) visited Cascade Pass in 1898, he Lehmer, Paddy McCarthy, Geoffry Phelps, Kea Umstadt, Carl began a geologic exploration which would blossom only after Wentworth, and Karen Wheeler. three-quarters of a century of growing geologic theory. The Paleontologists who helped immensely by identifying region encompassed by the Sauk River quadrangle is so struc- deformed, commonly recrystallized, and usually uninspiring turally complex that when Misch (1952) and his students fossils are Charles Blome, William Elder, Anita Harris, David began their monumental studies of the North Cascades in L. Jones, Jack W. Miller, and Kate Schindler. Chuck Blome 1948, the available geologic tools and theories were barely has been particularly helpful (see table 1). adequate to start deciphering the history. Subsequently, Bryant We thank John Whetten, Bob Zartman, and John Stacey (1955), Danner (1957), Jones (1959), Vance (1957a), Ford and his staff for unpublished U-Pb isotopic analyses (cited (1959), and Tabor (1961) sketched the fundamental outlines of in table 2).
    [Show full text]
  • S That Tree Dead? Quantifying Fire-Killed Trees to Inform Salvage and Forest Management
    United States Department of Agriculture Rocky Mountain Research Station Science You Can Use Bulletin SEPTEMBER 2019 | Issue 36 Is That Tree Dead? Quantifying Fire-Killed Trees to Inform Salvage and Forest Management In fire-dependent forests of the SUMMARY western United States, tree species adapt in several ways to survive Wildfires are natural disturbances in fire. In low-elevation forests that the western United States. Managing evolved with frequent, low-severity the resulting stands of dead and fire, many species have thick dying trees requires balancing bark protecting the living tissues conflicting priorities. Although these trees provide wildlife habitat and of cambium and phloem from salvage logging revenue, they also wildfires’ destructive heat. Longer, pose public safety hazards. thicker needles or those enclosed in One criticism of salvage logging is thick scales protect growing buds. that forest managers may overpredict Some tree species even shed their tree mortality and remove trees lower branches, which reduces the that will recover from their wildfire injuries. Sharon Hood, a research chance of fire climbing into their ecologist with the Rocky Mountain crowns. Still other tree species are Research Station, has studied tree easily killed by fire but can readily mortality following wildfires to identify resprout, or their seeds survive characteristics of fire injuries that will result in tree death. Through to quickly regenerate burned her research over the past decade, areas. Collectively, these adaptive she has improved the First Order measures allow species survival in Fire Effects Model (FOFEM), a modeling tool that forest managers fire-prone areas. However, high- can use to predict tree mortality intensity wildfires can generate and subsequently plan for salvage temperatures that overwhelm a and other management activities.
    [Show full text]
  • Snohomish County Hiking Guide
    2015- 2016 TO OUTDOOR ADVENTURE! 30 GREAT HIKES • DRIVING DIRECTIONS MAPS • ACCOMMODATIONS • LOCAL RESOURCES photo by Scott Morris PB | www.snohomish.org www.snohomish.org | 1 SCTB Print - Hiking Guide Cover 5.5” x 8.5” - Full Color 5-2015 HIKE NAME 1 Hike subtitle ROUNDTRIP m ile ELEVATION GAIN m ile HIKING SEASON m ile MAP m ile NOTES m ile DRIVING DIRECTIONS m ile CONTACT INFO m ile Hard to imagine, but one of the finest beaches River Delta. A fairly large lagoon has developed on in all of Snohomish County is just minutes from the island where you can watch for sandpipers, downtown Everett! And this two mile long sandy osprey, kingfishers, herons, finches, ducks, and expanse was created by man, not nature. Beginning more. in the 1890s, the Army Corp of Engineers built a You won’t be able to walk around the island as the jetty just north of Port Gardiner—then commenced channel side contains no beach. But the beach to dredge a channel. The spoils along with silt and on Possession Sound is wide and smooth and you sedimentation from the Snohomish River eventually can easily walk 4 to 5 miles going from tip to tip. created an island. Sand accumulated from tidal Soak up views of the Olympic Mountains; Whidbey, influences, birds arrived and nested, and plants Camano, and Gedney Islands; and downtown Everett soon colonized the island. against a backdrop of Cascades Mountains. In the 1980s the Everett Parks and Recreation Department began providing passenger ferry service to the island. Over 50,000 folks visit this sandy gem each year.
    [Show full text]
  • Lolo National Forest This Report Contains the Best Available Information at the Time of Publication
    Schedule of Proposed Action (SOPA) 04/01/2018 to 06/30/2018 Lolo National Forest This report contains the best available information at the time of publication. Questions may be directed to the Project Contact. Expected Project Name Project Purpose Planning Status Decision Implementation Project Contact R1 - Northern Region, Occurring in more than one Forest (excluding Regionwide) Bob Marshall Wilderness - Recreation management In Progress: Expected:04/2015 04/2015 Debbie Mucklow Outfitter and Guide Permit - Special use management Scoping Start 03/29/2014 406-758-6464 Reissuance [email protected] CE Description: Reissuance of existing outfitter and guide permits in the Bob Marshall Wilderness Complex. Web Link: http://www.fs.usda.gov/project/?project=44827 Location: UNIT - Swan Lake Ranger District, Hungry Horse Ranger District, Lincoln Ranger District, Rocky Mountain Ranger District, Seeley Lake Ranger District, Spotted Bear Ranger District. STATE - Montana. COUNTY - Flathead, Glacier, Lewis and Clark, Missoula, Pondera, Powell, Teton. LEGAL - Not Applicable. Bob Marshall Wilderness Complex. FNF Plan Revision & NCDE - Land management planning In Progress: Expected:05/2018 06/2018 Joseph Krueger GBCS Amendment to the Lolo, Objection Period Legal Notice 406-758-5243 Helena, Lewis & Clark,and 12/14/2017 [email protected] Kootenai NFs Description: The Flathead NF is revising their forest plan and preparing an amendment providing relevant direction from the EIS NCDE Grizzly Bear Conservation Strategy into the forest plans for the Lolo, Helena, Kootenai, and Lewis & Clark *UPDATED* National Forests. Web Link: http://www.fs.usda.gov/goto/flathead/fpr Location: UNIT - Kootenai National Forest All Units, Lewis And Clark National Forest All Units, Flathead National Forest All Units, Helena National Forest All Units, Lolo National Forest All Units.
    [Show full text]
  • Sherwood Mine Is in Fluvial Rocks of the Eocene Sanpoil Volcanics (Waggoner, 1990, Geol
    Okanogan Tough Nut (434) ALTERNATE NAMES DISTRICT COUNTY Okanogan 0 • PRIMARY QUADRANGLE SCALE 1h x 1° QUAD 1° X 2° QUAD Conconully East 1:24,000 Oroville Okanogan LATITUDE LONGITUDE SECTION, TOWNSHIP, AND RANGE 48° 34' 46.84" N 119° 44' 55.56" w NWl/4 sec. 31, 36N, 25E, elev. 3,200 ft LOCATION: elev. 3,200 ft HOST ROCK: NAME LITHOLOGY AGE metamorphic complex of Conconully schist pre-Jurassic ASSOCIATED IGNEOUS ROCK: DESCRIPTION AGE Conconully pluton Cretaceous COMMODIDES ORE MINERALS NON-ORE MINERALS Ag galena pyrite, quartz Pb chalcopyrite Cu sphalerite Zn DEPOSIT TYPE MINERALIZATION AGE vein Cretaceous? PRODUCTION: Production prior to 1901 was valued at $9,000 (Moen, 1973). TECTONIC SETTING: The Triassic sediments were deposited along an active margin associated with an island arc. The Conconully pluton is a directionless, post-tectonic body that was intruded into a major structural zone (Stoffel, K. L., OGER, 1990, oral commun.). ORE CONTROLS: The quartz vein is in quartz-mica schist is 3-10 ft wide, strikes N25W, and dips 60SW (Moen, 1973, p. 28). GEOLOGIC SETTING: The vein is in quartz-mica schist of the metamorphic complex of Conconully near the contact • with the Conconully pluton of Cretaceous age (Stoffel, 1990, geol. map). COMMENTS: The mine was developed by a 50-ft inclined shaft and a 250-ft adit with a 40-ft winze (Moen, 1973, p. 28). REFERENCES Huntting, M. T., 1956, Inventory of Washington minerals-Part II, Metallic minerals: Washington Division of Mines and Geology Bulletin 37, v. 1, 428 p.; v. 2, 67 p. Jones, E.
    [Show full text]
  • The Mountaineer 1978
    THE' MOUNTAINEER THE MOUNTAINEER 1978 Published July, 1979 Cover: Mountain Hemlock (Ramona Hammerly) 2 The Mountaineer (USPS 366-700) EDITORIAL COMMITTEE Mary Nysether, Managing Editor; Verna Ness, Production Editor; Christa Lewis, Assistant Editor; Herb Belanger, Don Brooks, Mary Leberg, Mariann Schmitt, Laura Swan, Cindy Vollmer, Mary Jane Ware. Writing, graphics and photographs should be submitted to the Editor, The Mountaineer, at the address below, before Janu­ ary 15, 1980 for consideration. Photographs should be black and white prints, at least 5x7 inches, with caption and photographer's name on back. Manuscripts should be typed double-spaced, with at least 1 Y2 inch margins, and include wri­ ter's name, address and phone number. Graphics should have caption and artist's name on back. Manuscripts cannot be re­ turned. Properly identified photographs and graphics will be returned about July. Copyright @1979 by The Mountaineers. Entered as second­ class matter April 8, 1922, at Post Office, Seattle, Washington, and additional offices under the act of March 3, 1879. Published monthly, except July, when semi­ monthly, by The Mountaineers, 719 Pike Street, Seattle, Washington 98101. 3 THE MOUNTAINEERS Purposes To explore and study the mountains, forests, and watercourses of the Northwest; To gather into permanent form the history and traditions of this region; To preserve by the encouragement of protective legislation or otherwise the natural beauty of Northwest America; Tomake expeditions into these regions in fulfillment of the above purposes; To encourage a spirit of good fellowship among all lovers of out­ door life. t � ----..:::::- -""°"'� ---������0wiw.=-- --- Firs at Excelsior Pass, North Cascades. Susan Marsh 4 Black-capped chickadee.
    [Show full text]
  • Reprint 8. Emplacement of the Twin Sisters Dunite, Washington
    STATE OF WASHINGTON ALBERT D. ROSELLINI, Governor Department of Conservation EARL COE, Director DIVISION OF MINES AND GEOLOGY MARSHALL T. HUNTIING, Supervisor Reprint No. 8 EMPLACEMENT OF THE TWIN SISTERS DUNITE, WASHINGTON By DONAL M. RAGAN Reprinted from American Journal 0£ Science, vol. 261, June 1963, p. 549-565 1963 [AMERICA N JoURNAL OF SCIENCE, VOL. 261, JUNE 1963, P. 549-565) EMPLACEMENT OF THE TWIN SISTERS DUNITE, WASHINGTON DONAL M. RAGAN Geology Department, University of Alaska, College, Alaska ABSTRACT. The large, elliptical, 36-square-mile Twin Sisters duuite and two smaller dunite bodies are located along a northwest-trending, nearly vertical fault and are intru· sive into several thrust plates and locally into the unconformably overlying Swauk forma­ tion. The time of emplacement was post-Paleocene, and definitely later than the main Cretaceous orogeny. The Twin Sisters mass is composed of a virtually unaltered, coarse-grained enstatite· bearing dunite, with accessory amounts of chromite and chromium diopside. Every section displays abundant evidence of cataclasis, including granulation and bending of mineral grains, and translation bands in olivine. Completely identical textures have recrystallized. These recrystallized cataclastic features now consist of fine-grained, unstrained olivine mosaic zones surrounding and embaying large, strained porphyroclasts. Locally thin mosaic zones cut single, large crystals. The translation bands have recrystallized into bandlike forms with irregular, sutured boundaries. This recrystallization is thought to have taken place at moderate temperatures. Serpentinites are marginal to and gradational with the large Twin Sisters mass and one exposed smaller body. The width of this nalTOW marginal zone is essentially the same for both the large and the small, and is thus independent of the size of the mass.
    [Show full text]
  • PM2.5 2017 Exceptional Events in Libby Due to Wildfires
    PM2.5 2017 Exceptional Events in Libby due to Wildfires Source: CIRA and NOAA. These data are preliminary and not operational. Prepared by: Montana DEQ February 2019 Contents 1. Summary ............................................................................................................................................... 3 2. Conceptual Model ................................................................................................................................. 6 3. Comparison to Historical Data .............................................................................................................. 7 4. Clear Causal Relationship .................................................................................................................... 10 Tuesday, August 08, 2017 .............................................................................................................. 10 Wednesday, August 09, 2017 ........................................................................................................ 17 Thursday, August 10, 2017 ............................................................................................................ 23 Friday, August 11, 2017 ................................................................................................................. 28 Monday, September 04, 2017 ....................................................................................................... 33 Tuesday, September 05, 2017 ......................................................................................................
    [Show full text]
  • Mineral Properties
    State of Washington ARTHUR B. LANGLIE, Governor Department of Conservation and Development ED DAVIS, Director DIVISION OF GEOLOGY HAROLD E. CULVER, Supervisor Report of Investigations No. 6 INVENTORY OF MINERAL PROPERTIES IN Snohomish County, Washington By W. A. BROUGHTON OLYMPIA STATE PRINTING PLANT 1942 For sale by Depa.rtment of Conservation and Development, Olympia, Washington. Price, 25 Cents. CONTENTS Page Introduct_ion ................................................. 5 Lode mining properties by districts . 7 Darrington Mining District. 7 General features . 7 Mines ............................ :. 7 Prospects . 8 Glacier Peak Mining District. H General features . 11 Prospects ................................. : ......... 11 Granite Falls Mining District. 12 General features . 12 Mines ................. ............................. 13 Prospects ............... ........................... 13 Index Mining District .................................... 13 General features . 13 Mines ....................... , ....................... 14 Prospects ........... ..................... ............ 16 Monte Cristo Mining District. 19 General features . • . 19 Mines ............................................... 20 Prospects . 22 Silver Creek Mining District. 27 General features . 27 Mines ................................................ 28 Prospects . 29 Silverton Mining District ...... .. ........................ 39 General features . 39 Mines ............................................... 39 Prospects . 40 Sultan Mining District. ... 46
    [Show full text]