Coastal Flood Impact Assessments for Alaska Communities

Coastal Flood Impact Assessments for Alaska Communities
Author: Richard Michael Buzard
Publisher:
Total Pages: 16
Release: 2021
Genre: Coastal engineering
ISBN:

Coastal communities in Alaska experience frequent storm surge flooding, yet the majority do not have a clear and consistent record of flooding. Local and statewide flood mitigation decisions require a clear understanding of flood risk, but the risk for many communities has not been adequately determined due to the difficulty of discovering information or interpreting flood impacts. One key dataset that is commonly missing is a complete list of all known flood events, along with flood heights relative to a consistent vertical datum, for each community. Water level sensors are largely absent in rural Alaska so determining the height of past events requires more creative efforts. This report introduces a method for estimating historical storm heights and flood impact categories for individual communities relative to infrastructure and a local tidal datum. Community-based observations and written accounts are used to estimate the height of recorded flood events. Flood impact categories are defined using National Weather Service terminology and are based on the elevation of residences, airstrips, and other critical infrastructure. Flood category heights and storm heights are listed in two tables, providing weather forecasters with fast decision support tools to help determine how communities should prepare for incoming storms. This initial publication includes reports for Golovin and Hooper Bay, and additional community assessments will follow. Community-specific reports include a flood category map showing current infrastructure, and a graphic relating infrastructure heights with previous floods. The report explains how each storm height was measured, and provides a bibliography of sources that were used to make those estimates.

Alaska Coastal Mapping Gaps & Priorities

Alaska Coastal Mapping Gaps & Priorities
Author: Jacquelyn R. Overbeck
Publisher:
Total Pages: 34
Release: 2018
Genre: Cartography
ISBN:

"This document is meant to define coastal baseline data, provide guidance on which communities in Alaska still lack baseline data, what data are missing, and the decision-making products to which baseline data can contribute."--Page 1

Coastal Hazard Analyses and Projections for Arctic Alaska Communities

Coastal Hazard Analyses and Projections for Arctic Alaska Communities
Author:
Publisher:
Total Pages: 0
Release: 2023
Genre: Coast changes
ISBN:

Storms and a changing climate can cause disasters for coastal communities. This is particularly felt in the Arctic, where temperatures are rising faster than the global average and sea ice decline has led to a longer open-water period when storms can make landfall. Communities in western and northern Alaska have experienced decades of frequent flooding and erosion. Climate change is a significant contributor today and for the future, but the current prevalence of disaster loss is more closely related to the continued development within hazard-prone areas. This dissertation maps areas prone to erosion and flooding to provide decision-making products for adaptation planning. Long-term erosion rates are projected 60 years into the future to compute the time until infrastructure is undermined. Flood histories are quantified to map hazard areas and improve storm impact forecasts. Record flood levels are estimated to support floodplain mapping. These studies are primarily exposure analyses that compare existing hazards to existing infrastructure to identify at-risk and safe areas around communities. However, as climate change progresses, existing hazards will change in unanticipated ways. The erosion history of Port Heiden tells an important story about how an unexpected change in coastal barrier islands led to rapid erosion and forced the community to relocate inland. This dissertation fills in the long-standing baseline data gaps about hazards in Arctic Alaska coastal communities. These results will help communities develop outside of hazard prone areas. However, the next iterations of hazard analyses will need to build off this baseline and carefully apply climate-informed approaches to predict changing hazards. Moreover, risk assessments must address community priorities and be improved by incorporating more of the values of mixed subsistence economies common to this region. Through community collaboration, hazard exposure analyses like this dissertation, and improving geophysical models, a roadmap is being built for communities to navigate towards a safer future.

Shoreline Change at Alaska Coastal Communities

Shoreline Change at Alaska Coastal Communities
Author: Jacquelyn R. Overbeck
Publisher:
Total Pages: 45
Release: 2020
Genre: Alaska
ISBN:

Many of Alaska’s coastal communities are vulnerable to erosion, flooding, and permafrost degradation. However, few vulnerability assessment tools are available to the public that are complete or that utilize transparent, consistent, and quantitative methods at a scale needed for local planning. This report summarizes statewide analyses of long-term shoreline change at 48 Alaska communities. Shoreline datasets were compiled from previously published U.S. Geological Survey assessments for northern Alaska, as well as created from historical and recent aerial images by the Alaska Division of Geological & Geophysical Surveys for western Alaska. Shorelines were analyzed to calculate rates of shoreline change every 82 feet (25 meters) along coastlines and tidally influenced river banks. In northern and western Alaska, 57 percent (27 of 48 total) of communities had erosion rates greater than 3.3 feet per year (1 meter per year) over the past 60 years. Maps of shoreline change and erosion rates are included here in a small map format for use by local community entities for planning and communication with state and federal agencies. Shoreline change rates alone do not describe community vulnerability, which may also depend on the location of infrastructure and the capacity of a community to respond to erosion, as well as other factors. Shoreline change rates were determined from historical data. Future rates of shoreline change may be influenced by coastal management and changes to environmental conditions that may result from climate change.

Coastal Erosion Protection and Community Relocation, Shishmaref, Alaska

Coastal Erosion Protection and Community Relocation, Shishmaref, Alaska
Author: Peter P. Schweitzer
Publisher:
Total Pages: 146
Release: 2005
Genre: Communities
ISBN:

Study investigates the possible social and cultural impact of relocating the population of Shishmaref to either Nome or Kotzebue if the Shishmaref region becomes uninhabitable due to erosion. Historical incidences of community relocation are examined, and citizens of Shishmaref, Nome, and Kotzebue are interviewed to assess the possible effects of relocation on all communities involved.

Color-indexed Elevation Maps for Flood-vulnerable Coastal Communities in Western Alaska

Color-indexed Elevation Maps for Flood-vulnerable Coastal Communities in Western Alaska
Author: Timothy Tschetter
Publisher:
Total Pages: 17
Release: 2014
Genre: Flood forecasting
ISBN:

This map series is a joint effort by the Alaska Division of Geological & Geophysical Surveys and the National Weather Service to merge best-available datasets into a tool that can streamline communication about forecasted water levels, local elevations, and potentially impacted infrastructure during storm events that may cause coastal flooding. These maps are not designed to function as flood inundation maps, but to serve as a temporary tool to communicate about elevations in at-risk coastal communities until true inundation mapping can be completed. Pilot work to test the usefulness of this map format is presented for five communities: Kivalina, Shishmaref, Golovin, Shaktoolik, and Unalakleet.

Color-indexed Elevation Maps for Flood-vulnerable Coastal Communities in Western Alaska

Color-indexed Elevation Maps for Flood-vulnerable Coastal Communities in Western Alaska
Author: Jacquelyn Overbeck
Publisher:
Total Pages:
Release: 2017
Genre: Brevig Mission (Alaska)
ISBN:

This map series is a joint effort by the Alaska Division of Geological & Geophysical Surveys and the National Weather Service to merge best-available datasets into a tool that can streamline communication about forecasted water levels, local elevations, and potentially impacted infrastructure during storm events that may cause coastal flooding. These maps are not designed to function as flood inundation maps, but to serve as a temporary tool to communicate about elevations in at-risk coastal communities until true inundation mapping can be completed. Pilot work to test the usefulness of this map format is presented for five communities: Kivalina, Shishmaref, Golovin, Shaktoolik, and Unalakleet.