The Arctic region is warming faster than anywhere else in the nation. Understanding the rates and causes of coastal change in Alaska is needed to identify and mitigate hazards that might affect people and animals that call Alaska home.
During research trips near the tiny village of Wainwright on Alaska’s North Slope, USGS scientist Li Erikson has encountered native in-ground cellars along the bluff’s edge. Alaska natives have called this rugged region of frozen tundra home for generations, yet modern conveniences such as sewage lines and grocery stores are not found in many areas this far north. So for years the indigenous people have used their naturally cold surroundings to their advantage—instead of modern refrigeration, they dig holes in the permafrost about 10 feet deep and 5 feet long to preserve the food that sustains them. However, as the permafrost thaws and coastal erosion increases, some of these natural iceboxes are beginning to disappear.
Issue
Alaska’s North Slope is home to the Iñupiat people, their archeological sites, and food resources that have sustained them for millennia. This area is a major migratory path for several bird species and other important Department of Interior trust species, such as polar bears. Prudhoe Bay is at the center of oil and gas production in Alaska and the site of numerous exploration wells and pipelines, which are at risk from spills, leaks, and inundation. Sandbags and shore protection structures have been emplaced to protect land and infrastructure in many of the villages and oil and gas production facilities. For example, on Barter Island, the airport runway is being relocated to higher ground to escape increased flooding and erosion by storm waves.
Although Alaska’s north coast experiences both erosion and accretion, it is predominantly erosional, retreating on average about 1.4 meters per year; very high rates of erosion—up to 20 meters per year—occur along some sections of coast, such as Drew Point, Alaska. The numerous low-lying barrier islands—which provide habitat for nesting birds, buffer wave energy reaching the mainland coast, and regulate salt and freshwater exchange in the lagoons—are extremely mobile and experience high rates of both erosion and accretion.
Ocean pack ice borders the coast from October to July and normally protects the barrier islands and mainland coast against winter storm flooding and erosion. The ice now forms later than in previous years, thus lengthening the ice-free period. Delayed formation of sea ice raises the potential for damage to the coast from storms arriving later in the season. It’s still uncertain whether these late storms are increasing in intensity.
In addition, the tundra typically has an upper active layer, which is the zone above the permafrost that thaws in summer and refreezes in winter. The active layer appears to be thickening in some regions each year; exactly where and why this is happening is unknown, but it may be linked to why the bluffs are failing. The release of large amounts of carbon and methane associated with permafrost degradation is also of concern.
Human adaptation to these changes is also difficult. Though major infrastructure in villages can be moved, relocation comes at great cost and with some concern that new sites might also be at risk from future erosion. Gathering baseline data on Alaska’s changing shoreline and the forces that are driving change can help scientists develop models of a future shoreline. This research can help government officials protect villages, mitigate threats to oil and gas infrastructure, and manage habitat for endangered and threatened species.
What the USGS is doing
The USGS team aims to determine the dominant forces causing beach and bluff erosion. To do this, they are modeling sea-level rise combined with projected storm activity to create maps of likely inundation—the first 21st-century flood maps of the area. They are examining the physical characteristics of the bluffs, the beach, and the nearby seafloor. Physical measurements collected in the field are vital to feed into models to understand how this wild landscape is evolving.
To quantify bluff erosion, scientists map the bluff edges using portable GPS units. After collecting samples of sediment on the beach and seafloor, the scientists measure its composition and grain size to help them model how waves and currents transport sediment. To monitor permafrost temperatures, scientists drill holes into the permafrost to place temperature sensors, or thermistor arrays. They also measure the thickness of the active layer. Resistivity instruments placed in the ground can be used to calculate how much of the ground is resistant to electrical conductivity. As ice does not conduct electricity, these measurements will indicate the presence of ice and fluctuations of the permafrost thickness. Knowing how the depth of the active layer varies throughout the summer warming period can help the team determine if this dynamic makes bluffs more susceptible to failure. In addition, collecting soil samples helps USGS microbiologists assess the role of microbes in the changing tundra.
To gain an initial understanding of the landscape where they would be working, the team flew the coast in 2006 and 2009 to collect 7,800 digital photographs and about 20 hours of continuous video along an 800-kilometer stretch of coast from Cape Sabine, Alaska, to the U.S.–Canada border. This effort was part of the USGS National Assessment of Shoreline Change project, designed to document and evaluate beach erosion along U.S. open-ocean shorelines. In Alaska, historical data on shoreline positions and coastal elevation are limited. Whereas records date back 150 years for most of the United States, Alaska’s historical shoreline maps, where they exist, go back only to the 1940s. It is extremely challenging to assess shoreline changes based on a paucity of data, in a region undergoing complex changes to ice cover, land subsidence, and shoreline position.
Using digitized historical maps from the 1940s and aerial and satellite imagery from the 2000s, the team calculated shoreline-change rates every 50 meters, which divided the coastline into nearly 27,000 sections. Airborne lidar surveys were collected between Icy Cape and the U.S.–Canada border (a stretch of coast about the length of California) over the course of four years in cooperation with the Arctic Landscape Conservation Cooperative and the Bureau of Land Management. The team incorporated these elevation data into a data set that can be used to define the shoreline position at the time of collection (2009–2012), and will help inform models of coastal inundation and hazards.
These data and present-day elevation and shoreline maps are a starting point for monitoring future changes to Alaska’s landscape. Additionally, several time-lapse cameras around the island capture terrain and coastal changes. Watch multiple-month time-lapse videos of Barter Island’s north coast, with examples of slumping bluffs:
Getting people and gear to this remote region with limited amenities requires creative planning, and often requires help from partner agencies already established there, such as the U.S. Fish and Wildlife Service which has a permanent facility in Kaktovik. The team also engaged the community (the city of Kaktovik, the Kaktovik Iñupiat Corporation, and local residents) through outreach on USGS research activities.
Though vital and exciting frontier work, Arctic research does have its challenges—whether it’s walking on unstable bluffs in the fog, discovering fresh bear tracks following researchers’ footprints, or returning to a building to find a fire has destroyed much of the scientific gear. Transit into and out of Barter Island is often delayed due to inclement weather closing the small airstrip.
What the USGS has learned
Alaska’s north coast is predominantly erosional, averaging a loss of 1.4 meters a year. Along a much smaller stretch (60 kilometers) of this coastline (approximately box 6 in map below), USGS found that average annual erosion rates doubled from historical levels of about 20 feet per year between the mid-1950s and late-1970s, to 45 feet per year between 2002 and 2007. The study along that stretch of the Beaufort Sea also verified the disappearance of cultural and historical sites, including Esook, a hundred-year-old trading post now underwater on the Beaufort Sea floor, and Kolovik (Qalluvik), an abandoned Iñupiaq village site that may soon be lost.
The change in erosion rates is likely the result of several changing Arctic conditions, including declining sea-ice extent, increasing summertime sea-surface temperature, rising sea level, and possible increases in storm power and corresponding wave action. More long-term work is needed to understand the interplay of these factors and how they drive changes in coastal erosion.
This research is part of the USGS project titled, “Coastal Climate Impacts.”
Explore other research topics associated with this project, below.
Coastal Climate Impacts
Dynamic coastlines along the western U.S.
Low-lying areas of tropical Pacific islands
Climate impacts on Monterey Bay area beaches
Using Video Imagery to Study Wave Dynamics: Unalakleet
Using Video Imagery to Study Sediment Transport and Wave Dynamics: Nuvuk (Point Barrow)
Estuaries and large river deltas in the Pacific Northwest
Using Video Imagery to Study Coastal Change: Barter Island, Alaska
- Overview
The Arctic region is warming faster than anywhere else in the nation. Understanding the rates and causes of coastal change in Alaska is needed to identify and mitigate hazards that might affect people and animals that call Alaska home.
During research trips near the tiny village of Wainwright on Alaska’s North Slope, USGS scientist Li Erikson has encountered native in-ground cellars along the bluff’s edge. Alaska natives have called this rugged region of frozen tundra home for generations, yet modern conveniences such as sewage lines and grocery stores are not found in many areas this far north. So for years the indigenous people have used their naturally cold surroundings to their advantage—instead of modern refrigeration, they dig holes in the permafrost about 10 feet deep and 5 feet long to preserve the food that sustains them. However, as the permafrost thaws and coastal erosion increases, some of these natural iceboxes are beginning to disappear.
Sources/Usage: Public Domain.Native in-ground ice cellars can disappear as bluffs erode and permafrost thaws, such as this one in Wainwright, Alaska.
Sources/Usage: Public Domain.This airport runway, the main lifeline for inhabitants on Barter Island, floods annually during storms. A new runway is being built farther inland on higher ground. Issue
Alaska’s North Slope is home to the Iñupiat people, their archeological sites, and food resources that have sustained them for millennia. This area is a major migratory path for several bird species and other important Department of Interior trust species, such as polar bears. Prudhoe Bay is at the center of oil and gas production in Alaska and the site of numerous exploration wells and pipelines, which are at risk from spills, leaks, and inundation. Sandbags and shore protection structures have been emplaced to protect land and infrastructure in many of the villages and oil and gas production facilities. For example, on Barter Island, the airport runway is being relocated to higher ground to escape increased flooding and erosion by storm waves.
Although Alaska’s north coast experiences both erosion and accretion, it is predominantly erosional, retreating on average about 1.4 meters per year; very high rates of erosion—up to 20 meters per year—occur along some sections of coast, such as Drew Point, Alaska. The numerous low-lying barrier islands—which provide habitat for nesting birds, buffer wave energy reaching the mainland coast, and regulate salt and freshwater exchange in the lagoons—are extremely mobile and experience high rates of both erosion and accretion.
In the spring, winter sea ice thaws and moves offshore leaving the coast exposed to increased wave action and relatively warm water temperatures that, when in contact with the bluff, erodes the toe of the bluff. Additionally, warm air temperatures during the spring and summer months thaw the upper layers of permafrost causing erosion or sloughing of the bluff face above the water line. In the fall, air temperatures begin to decrease again, but wave action and contact with the bluff continues; upper layers of the bluffs often topple over and erode in large chunks at this time. In late fall and early winter, sea ice reforms, once again protecting the coast from wave action. Recorded June 1, 2019 - August 18, 2019: Video shows a series of photos taken every hour during daylight hours in the summer of 2019. The camera looks westward along the coastal bluffs of Barter Island, located on Alaska’s North Slope. A pole on the bluff, visible in the first half of the video, once supported another video camera that was aimed at the shoreline to study wave and shoreline dynamics.This video starts on June 1st at -4°C (25° F) when the bluffs are still frozen, snow is on the ground, and the winter pack ice protects the permafrost cliffs from wave attack. By the end of June, the ice and snow are gone, temperatures often climb to 12°C (54° F), and waves begin to lap at the narrow beach below the bluffs.In mid-July, the now-thawed, upper active layer of the tundra begins to slough off onto the beach. By the end of July, waves accompanied with elevated storm-tides erode the lower part of the slope. Just days later, as erosion increases rapidly, the bluff supporting the camera gives way and the camera tumbles onto the beach. Despite its fall onto the muddy beach, the camera continued to record and was successfully recovered in order to create this video.The USGS is studying this highly erosive stretch of Arctic coastline to try to better understand the main driving forces behind the erosion and why erosion rates seem to be increasing. The increase is likely the result of several changing arctic conditions, including declining sea-ice extent, increasing summertime sea-surface temperature, rising sea level, and possible increases in storm power and corresponding wave action. More long-term work is needed to understand the interplay of these factors and how they drive changes in coastal erosion. This time-lapse of Barter Island in Alaska during three summer months in 2014, shows the pack ice melting and the subsequent effects to the beach and permafrost cliffs from storms and summer temperatures. This camera sat on a fallen snow fence to capture storm events. As more storms hit the coast, winter ice no longer sticks around long enough to buffer them, and the waves eat away at the base of the bluffs. In three instances you can see sections of the cliff slump as it thaws. In fact, the camera taking this imagery starts to tilt as the ground beneath it begins to slump. Villages exist along this northern stretch of coastal Alaska where erosion may be caused by several environmental elements.
Ocean pack ice borders the coast from October to July and normally protects the barrier islands and mainland coast against winter storm flooding and erosion. The ice now forms later than in previous years, thus lengthening the ice-free period. Delayed formation of sea ice raises the potential for damage to the coast from storms arriving later in the season. It’s still uncertain whether these late storms are increasing in intensity.
In addition, the tundra typically has an upper active layer, which is the zone above the permafrost that thaws in summer and refreezes in winter. The active layer appears to be thickening in some regions each year; exactly where and why this is happening is unknown, but it may be linked to why the bluffs are failing. The release of large amounts of carbon and methane associated with permafrost degradation is also of concern.
Human adaptation to these changes is also difficult. Though major infrastructure in villages can be moved, relocation comes at great cost and with some concern that new sites might also be at risk from future erosion. Gathering baseline data on Alaska’s changing shoreline and the forces that are driving change can help scientists develop models of a future shoreline. This research can help government officials protect villages, mitigate threats to oil and gas infrastructure, and manage habitat for endangered and threatened species.
Sources/Usage: Public Domain.USGS researcher Benjamin Jones measures erosion near a collapsed block of ice-rich permafrost along Alaska's Arctic coast.
Sources/Usage: Public Domain.A handheld auger is used to drill holes into the permafrost to place temperature sensors. What the USGS is doing
The USGS team aims to determine the dominant forces causing beach and bluff erosion. To do this, they are modeling sea-level rise combined with projected storm activity to create maps of likely inundation—the first 21st-century flood maps of the area. They are examining the physical characteristics of the bluffs, the beach, and the nearby seafloor. Physical measurements collected in the field are vital to feed into models to understand how this wild landscape is evolving.
To quantify bluff erosion, scientists map the bluff edges using portable GPS units. After collecting samples of sediment on the beach and seafloor, the scientists measure its composition and grain size to help them model how waves and currents transport sediment. To monitor permafrost temperatures, scientists drill holes into the permafrost to place temperature sensors, or thermistor arrays. They also measure the thickness of the active layer. Resistivity instruments placed in the ground can be used to calculate how much of the ground is resistant to electrical conductivity. As ice does not conduct electricity, these measurements will indicate the presence of ice and fluctuations of the permafrost thickness. Knowing how the depth of the active layer varies throughout the summer warming period can help the team determine if this dynamic makes bluffs more susceptible to failure. In addition, collecting soil samples helps USGS microbiologists assess the role of microbes in the changing tundra.
Sources/Usage: Public Domain.Figure shows aerial photography surveys along Alaska's northern coast, from the U.S.–Canada border to Cape Sabine during 2006 and 2009.
Sources/Usage: Public Domain.An oblique aerial photograph shows the currently active Long Range Radar Site on Barter Island, formerly a DEW Line (Distant Early Warning) station that was deactivated in 1990. The Cold War-era landfill in the foreground of the photograph was at immediate risk from coastal erosion in 2006 and has since been relocated farther inland. To gain an initial understanding of the landscape where they would be working, the team flew the coast in 2006 and 2009 to collect 7,800 digital photographs and about 20 hours of continuous video along an 800-kilometer stretch of coast from Cape Sabine, Alaska, to the U.S.–Canada border. This effort was part of the USGS National Assessment of Shoreline Change project, designed to document and evaluate beach erosion along U.S. open-ocean shorelines. In Alaska, historical data on shoreline positions and coastal elevation are limited. Whereas records date back 150 years for most of the United States, Alaska’s historical shoreline maps, where they exist, go back only to the 1940s. It is extremely challenging to assess shoreline changes based on a paucity of data, in a region undergoing complex changes to ice cover, land subsidence, and shoreline position.
Using digitized historical maps from the 1940s and aerial and satellite imagery from the 2000s, the team calculated shoreline-change rates every 50 meters, which divided the coastline into nearly 27,000 sections. Airborne lidar surveys were collected between Icy Cape and the U.S.–Canada border (a stretch of coast about the length of California) over the course of four years in cooperation with the Arctic Landscape Conservation Cooperative and the Bureau of Land Management. The team incorporated these elevation data into a data set that can be used to define the shoreline position at the time of collection (2009–2012), and will help inform models of coastal inundation and hazards.
Sources/Usage: Public Domain.USGS geologist Bruce Richmond prepares to deploy a pipe dredge that will be dragged along the seabed to collect sediment. These data and present-day elevation and shoreline maps are a starting point for monitoring future changes to Alaska’s landscape. Additionally, several time-lapse cameras around the island capture terrain and coastal changes. Watch multiple-month time-lapse videos of Barter Island’s north coast, with examples of slumping bluffs:
Getting people and gear to this remote region with limited amenities requires creative planning, and often requires help from partner agencies already established there, such as the U.S. Fish and Wildlife Service which has a permanent facility in Kaktovik. The team also engaged the community (the city of Kaktovik, the Kaktovik Iñupiat Corporation, and local residents) through outreach on USGS research activities.
Though vital and exciting frontier work, Arctic research does have its challenges—whether it’s walking on unstable bluffs in the fog, discovering fresh bear tracks following researchers’ footprints, or returning to a building to find a fire has destroyed much of the scientific gear. Transit into and out of Barter Island is often delayed due to inclement weather closing the small airstrip.
What the USGS has learned
Alaska’s north coast is predominantly erosional, averaging a loss of 1.4 meters a year. Along a much smaller stretch (60 kilometers) of this coastline (approximately box 6 in map below), USGS found that average annual erosion rates doubled from historical levels of about 20 feet per year between the mid-1950s and late-1970s, to 45 feet per year between 2002 and 2007. The study along that stretch of the Beaufort Sea also verified the disappearance of cultural and historical sites, including Esook, a hundred-year-old trading post now underwater on the Beaufort Sea floor, and Kolovik (Qalluvik), an abandoned Iñupiaq village site that may soon be lost.
The change in erosion rates is likely the result of several changing Arctic conditions, including declining sea-ice extent, increasing summertime sea-surface temperature, rising sea level, and possible increases in storm power and corresponding wave action. More long-term work is needed to understand the interplay of these factors and how they drive changes in coastal erosion.
Sources/Usage: Public Domain. Visit Media to see details.Map of the north coast of Alaska study area showing color-coded shoreline change rates, the boundaries of the ten analysis regions (dashed boxes and numbers), and key geographic locations discussed in the report "National Assessment of Shoreline Change: Historical Shoreline Change Along the North Coast of Alaska, U.S.-Canadian Border to Icy Cape," USGS Open-File Report 2015-1048)
Sources/Usage: Public Domain.Coastal villages throughout the Arctic region, such as Wainwright shown here, face significant erosion threats. - Science
This research is part of the USGS project titled, “Coastal Climate Impacts.”
Explore other research topics associated with this project, below.Coastal Climate Impacts
The impacts of climate change and sea-level rise around the Pacific and Arctic Oceans can vary tremendously. Thus far the vast majority of national and international impact assessments and models of coastal climate change have focused on low-relief coastlines that are not near seismically active zones. Furthermore, the degree to which extreme waves and wind will add further stress to coastal...Dynamic coastlines along the western U.S.
The west coast of the United States is extremely complex and changeable because of tectonic activity, mountain building, and land subsidence. These active environments pose a major challenge for accurately assessing climate change impacts, since models were historically developed for more passive sandy coasts.Low-lying areas of tropical Pacific islands
Sea level is rising faster than projected in the western Pacific, so understanding how wave-driven coastal flooding will affect inhabited, low-lying islands—most notably, the familiar ring-shaped atolls—as well as the low-elevation areas of high islands in the Pacific Ocean, is critical for decision-makers in protecting infrastructure or relocating resources and people.Climate impacts on Monterey Bay area beaches
For beach towns around Monterey Bay, preserving the beaches by mitigating coastal erosion is vital. Surveys conducted now and regularly in the future will help scientists understand the short- and long-term impacts of climate change, El Niño years, and sea-level rise on a populated and vulnerable coastline.Using Video Imagery to Study Wave Dynamics: Unalakleet
USGS scientists installed two video cameras atop a windmill tower in Unalakleet, Alaska, pointing westward over Norton Sound, to observe and quantify coastal processes such as wave run-up, development of rip channels, bluff erosion, and movement of sandbars and ice floes.Using Video Imagery to Study Sediment Transport and Wave Dynamics: Nuvuk (Point Barrow)
Two coastal observing video cameras are installed atop a utility pole near the northernmost point of land in the United States, at Nuvuk (Point Barrow), Alaska. The cameras point northwest toward the Arctic Ocean and the boundary between the Chukchi and Beaufort Seas, and will be used to observe and quantify coastal processes such as wave run-up, bluff erosion, movement of sandbars and ice floes...Estuaries and large river deltas in the Pacific Northwest
Essential habitat for wild salmon and other wildlife borders river deltas and estuaries in the Pacific Northwest. These estuaries also support industry, agriculture, and a large human population that’s expected to double by the year 2060, but each could suffer from more severe river floods, higher sea level, and storm surges caused by climate change.Using Video Imagery to Study Coastal Change: Barter Island, Alaska
For a short study period, two video cameras overlooked the coast from atop the coastal bluff of Barter Island in northern Alaska. The purpose was to observe and quantify coastal processes such as wave run-up, development of rip channels, bluff erosion, and movement of sandbars and ice floes. - Data
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