Landslide and Avalanche Assessment

Project Overview

The City and Borough of Juneau did not adopt these landslide hazard assessment maps. The landslide hazard assessment maps do not consider any human-made structures or mitigating measures. The landslide hazard assessment maps do not provide an indication of risk as would be necessary to determine whether landslide hazards actually pose a threat to specific properties. A more detailed site-specific investigation and evaluation would be required to determine risk to, and appropriate mitigations for, specific properties.

CBJ’s former hazard maps, adopted in 1987 for downtown Juneau, are based on maps created in the 1970s. These low-resolution maps combine landslide and avalanche areas into a single map with identifies moderate and severe hazard areas. The former maps are available here.

In 2018, the CBJ Community Development Department received a grant from the Federal Emergency Management Agency (FEMA) to update these maps with current scientific analysis, and to evaluate landslide and avalanche areas separately. Tetra Tech Inc. was hired as the contractor. Tetra Tech provided a first draft assessment in May 2021 with new maps.  In April 2022 Tetra Tech provided a final assessment with minor revisions to the primary document and maps, and supplemental memorandums. The contract with Tetra Tech expired on April 30, 2022. The grant expired on September 30, 2022.

The final assessment includes updated maps, memorandums with background information on areas of special concern, and a memorandum that explains how to interpret the maps.

At the CBJ Assembly December 11, 2023 regular meeting, the Assembly voted to adopt the 2022 Downtown Juneau Landslide and Avalanche Assessment avalanche maps. The Assembly did not adopt the landslide maps in the study. The Assembly also approved associated regulations for avalanche areas, and repealed the 1987 hazard maps.

The City and Borough of Juneau did not adopt these landslide hazard assessment maps. The landslide hazard assessment maps do not consider any human-made structures or mitigating measures. The landslide hazard assessment maps do not provide an indication of risk as would be necessary to determine whether landslide hazards actually pose a threat to specific properties. A more detailed site-specific investigation and evaluation would be required to determine risk to, and appropriate mitigations for, specific properties.

Recorded CBJ meetings, Agendas & Minutes

The final ordinance may be found HERE

Final Hazard Assessment

The project area map and final hazard assessment are available at the links below.

• Project Area Map
• Downtown Juneau Landslide and Avalanche Hazard Assessment April 27, 2022
  • 2022 Landslide Maps
  • 2022 Avalanche Maps
  • Appendix A Tetra Tech’s Limitations on Use of this Document
  • Appendix B Landslide Hazard Designation Mapping
  • Appendix C Technical Memos
    • Technical Memo 1: Landslide Mapping Accuracy and Modelling
    • Technical Memo 2: Landslide Designations and Boundaries – Bathe Creek and Highlands
    • Technical Memo 3: Mapping Overview Starr Hill Subdivision and Additional Information
    • Technical Memo 4:  Guide to Avalanche and Landslide Hazard Designations
    • Technical Memo 5: Landslide Hazard Designations at Telephone Hill and Gastineau Avenue
    • Technical Memo 6:  Severe Landslide Hazard Designations at Staff Hill and Gastineau Avenue
    • Technical Memo 7:  Considerations for Anthropogenic Terrain at Starr Hill and Gastineau Avenue
  • Appendix D Avalanche Modelling Parameters and Assumptions

Background Documents

• *NEW* Final Approved Ordinance
• *NEW* Assembly Regular Meeting 12-11-23 Meeting Minutes COMING SOON
• Assembly Committee of the Whole 11-6-23 Meeting Minutes
• Assembly Committee of the Whole 9-18-23 Meeting Minutes
• Assembly Regular Meeting 9-11-23 Meeting Minutes
• Assembly Committee of the Whole 8-28-23 Meeting Minutes
• Assembly Lands Housing and Economic Development Committee 7-17-23 Meeting Minutes
• Assembly Lands Housing and Economic Development Committee 6-26-23 Meeting Minutes
• Planning Commission Regular Meeting 5-23-23 Meeting Minutes
• Planning Commission Title 49 Committee 4-20-23 Meeting Materials and Video Recording
• Planning Commission Committee of the Whole 4-11-23 Meeting Minutes
• Planning Commission Committee of the Whole 3-14-23 Meeting Minutes
• Planning Commission Committee of the Whole 3-14-23 Meeting Materials
• Assembly Committee of the Whole 11-7-22 Video Recording (Hazard Mapping discussion begins at 1:37:25)
• Assembly Committee of the Whole 2-14-22 Meeting Minutes
• Assembly Committee of the Whole 9-20-21 Meeting Minutes
• Planning Commission 8-10-21 Meeting Minutes
• Planning Commission Notice of Recommendation to the Assembly 8-24-21
• Community Development Department Presentation to the Planning Commission 8-10-21
• Contractor Presentation to the Planning Commission 8-10-21
• Planning Commission Hazard Assessment Staff Report 8-10-21
• Public Meeting 7-21-21
  • Community Development Department Presentation
  • Tetra Tech Contractor Presentation
  • Public Meeting Question and Answer Session (Zoom recording)
  • Public Meeting Question and Answer Session Transcript
• Assembly resolution on the hazard mapping grant 12-18-17
• Maps prepared by CDD that show the difference between the adopted 1987 hazard maps and the 2022 landslide and avalanche maps.
  • CDD Adopted 1987 Combined Landslide-Avalanche Map
  • 2022 Final Avalanche Map Prepared by CDD
  • 2022 Final Landslide Map Prepared by CDD
  • 2022 Map with Difference Between 1987 Hazard Maps and 2022 Proposed Maps Prepared by CDD
• 1987 Landslide/Avalanche Maps
• Adopted Landslide/Avalanche Regulations
  • Hillside Development
  • Landslide and Avalanche Areas
• Hazard Studies

Public Notice

• Postcard mailings to all property owners within the Project Area were mailed on the following dates:

• • April 26, 2023 before the May 23, 2023 Planning Commission public hearing.
  • March 31, 2023 before the April 11, 2023 Planning Commission Committee of the Whole meeting.
  • March 7, 2023 before the March 14, 2023 Planning Commission Committee of the Whole meeting.
  • September 23, 2022, to meet FEMA’s September 30, 2023 grant requirement deadline to notify the public of the final document with technical memos.
  • July 22, 2021 before the August 10, 2021 public hearing with the Planning Commission and contractor.
  • July 9, 2021, before the July 21, 2021 public meeting with CDD and the contractor.
• Notice has also been provided in the Juneau Empire’s “Your Municipality” section in the two weeks before each Planning Commission meeting, and this special projects website has been updated frequently.
• The Community Development Department does not provide public notice to property owners for Assembly meetings.