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G-LiHT | A View From Above

July 21st, 2014 by Kathryn Hansen

Text by Doug Morton
NASA’s Goddard Space Flight Center

G-LiHT DSLR image of forests and open water near the Tetlin National Wildlife Refuge east of Tok, Alaska. Credit: NASA

G-LiHT DSLR image of forests and open water near the Tetlin National Wildlife Refuge east of Tok, Alaska. Credit: NASA

I have always enjoyed looking out the window of a plane. From the typical cruising altitude of a commercial jetliner, the view of lakes and fields and mountains is familiar (but still fascinating) to a NASA scientist used to looking at Earth from space. Vegetation and land use follow the topography in predictable ways — agricultural fields on the flattest lands and dense forest cover on the warm, south-facing slopes.

Spruce forest in the Yukon-Charley Rivers National Preserve north of Delta Junction, Alaska. Credit: Ross Nelson/NASA's Goddard Space Flight Center

Spruce forest in the Yukon-Charley Rivers National Preserve north of Delta Junction, Alaska. Credit: Ross Nelson/NASA’s Goddard Space Flight Center

In Alaska, the G-LiHT campaign is flying low and slow to provide a very detailed look at forest structure, topography, wetlands, and forest health. At 1,100 feet above ground level, the view from above is stunning. Looking down, you see individual trees, small polygons formed by permafrost, and subtle changes in topography that allow vegetation to flourish on dry ground or wallow in the wetlands of the Tanana flats. Small black spruce trees, barely head high and the width of a dinner plate, are packed together in stands too thick to walk through. Looking out, you can see the vast expanse of the Tanana Valley, a lush green carpet of forest. The braided channels of the river flash in the sunlight as the milky white water heads out of the mountains. Ahead, the steep rise of the Alaska Range signals the end of another flight line.

Seeing the landscape from the same perspective as the G-LiHT sensors provides essential context for the project. The G-LiHT operators on the plane can switch between the real-time view of the incoming data stream and the landscape below. G-LiHT PI Bruce Cook noted, “it’s a little dizzying to watch the imagery fly by on the screen, but matching the bird’s eye view to the data gives an idea of what is possible with the analysis and interpretation of the G-LiHT data.”

Update: As of July 19, the piper had flown more than 70 hours for data collection (9,300 miles), and with more than half of the planned flight lines in the Tanana region completed.

Rainbow over the Tanana River. Credit: Bruce Cook/NASA's Goddard Space Flight Center

Rainbow over the Tanana River. Credit: Bruce Cook/NASA’s Goddard Space Flight Center

 

NASA’s Alaska Forest Survey Kicks Off

July 14th, 2014 by Kathryn Hansen

From early July through mid-August 2014, scientist Doug Morton of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will be flying low over the treetops of interior Alaska. The purpose? First-of-a-kind look at the state’s forests with a portable, airborne imaging system called G-LiHT to map the composition, structure and function of the ecosystem.

According to Morton, key components of the fieldwork include:

“First, we are partnering with the U.S. Forest Service, as directed by the recently-passed Farm Bill, to incorporate remote sensing technology into forest monitoring efforts. Our pilot study will be the first inventory of forests in interior Alaska; a standard ground inventory (as in the lower 48) has always been too costly or logistically challenging to implement.

Second, we will study post-fire recovery, with plans to sample more than 80 percent of all fires in the Tanana region since 1950.  Fire is the major agent of change in interior Alaska, and understanding the patterns of forest recovery is essential to gauge the vulnerability/resilience of forests to future climate change.

Third, we will benchmark conditions (topography/permafrost, forest cover, forest composition) across a large portion of the Arctic-Boreal Vulnerability Experiment (ABoVE) science domain.”

Follow Morton through the summer as, Internet connection permitting, he sends updates and photos from the field.

 

 

The Pipeline Disaster That Wasn’t

February 5th, 2014 by David Wolfe

Editor’s Note: This guest post was written by David Wolfe, a remote sensing specialist working with the Global Land Ice Measurements from Space (GLIMS) project, and Jeffrey Kargel, a professor at the University of Arizona and the GLIMS project coordinator. Wolfe wrote his thesis for Alaska Pacific University about glacier-dammed lakes in Alaska and recently authored a book chapter on the same topic. Gregory Leonard, Michael Abrams, and Adam Voiland also contributed information for this post.

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The Advanced Land Imager (ALI) on the Earth Observing-1 satellite captured this scene of an avalanche in Keystone Canyon on January 31, 2014. Notice how debris has obscured sections of both the Richardson Highway and the Lowe River. Image by NASA Earth Observatory.

On January 24, 2014, an exceptionally large avalanche closed the Richardson Highway (Alaska Route 4), the only land link between the ice-free oil port of Valdez and the rest of Alaska. The avalanche was classified as a size 5, the largest category, though no one was hurt. The avalanche impounded the Lowe River, forming a lake. The lake drained within days of its formation, without an outburst flood, due in part to a 100 year-old abandoned railroad tunnel that shunted water around the dam. On February 5, 2014, officials reopen the road.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) obtained the image below, on January 29, 2014, upon request by the Global Land Ice Measurements from Space (GLIMS) consortium. The image is an oblique rendering of part of the ASTER image draped over the GDEM2, a global topographic shaded relief map that was produced from a dozen years worth of ASTER images. It is a standard false-color image taken in visible and near infrared wavelengths. Vegetation appears red; snow is white. If clean, water appears black; if slightly sediment laden, it is blue.

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Perspective rendering of an ASTER image on a shaded relief map, showing the location of the avalanche and impoundment lake relative to a portion of the Trans-Alaska Pipeline System and Richardson Highway. The image was acquired on January 29, 2014. Image by Gregory Leonard and Michael Abrams.

The ASTER image above shows the outlines of the avalanche source, the avalanche deposit, the maximum extent of the impoundment lake, and the routes of the Richardson Highway and the Trans Alaska Pipeline System (TAPS). The lake had partially drained when the image was acquired. At maximum extent, the lake apparently barely overlapped part of the route of the pipeline, but in this sector the pipeline is buried and was thus safe. Although the greater potential pipeline disaster was averted, the closure of the highway has been a significant inconvenience for many people in and near Valdez. Ferries into and out of Valdez were increased to assist stranded residents, and roadway commerce as far as Fairbanks must have been affected by the disruptions to the Richardson Highway.

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Crews from the Alaska Department of Transportation and Public Facilities (ADOT&PF) mobilized equipment on the south side of the road closure Thursday evening, January 30, 2014, and began 24-hour snow removal operations early Friday. The top photo shows a Hitachi 450 excavator, providing a scale that shows the avalanche to be 40 feet (12 meters) thick at this location. The next photo, just above, shows a daytime view of the night-and-day operations to reopen the highway. Elsewhere, reports have the avalanche approaching 100 feet (30 meters) thick. Photos courtesy of Robert Dunning and staff, Alaska DOT&PF, reproduced by permission.

The 1.35 square mile (3.5 square kilometer) source of the avalanche was estimated from the ASTER and ALI images and from news broadcast video taken from a helicopter by ADOT&PF, Alyeska Pipeline Service Co., the Anchorage Daily News, and Alaska Dispatch staff. The huge avalanche and 0.135 square mile (88-acre, 0.35 square kilometer) impoundment lake reminds us of the remarkable engineering of the Alaskan pipeline (below). The pipeline faces many natural hazards, including earthquakes, landslides, floods, forest fires, avalanches, glacier lake outburst floods, and thawing permafrost. In 2002, it survived the magnitude 7.9 Denali earthquake without rupturethough  just barely. Several key design tolerances were closely approached or exceeded, according to a report published in Earthquake Spectra. That earthquake and the 2014 avalanche did not cause a disaster because of the pipeline’s careful engineering, including the use of many novel technologies and special routing. Just about 1.9 miles (3 kilometers) upstream of the Lowe River crossing, the highway and pipeline traverses a creek that has been inundated by periodic outburst floods, some destructive, from a series of glacier-dammed lakes high in the mountains. TAPS was routed underground through the flood impact zone and over the Chugach Mountains. The specific routing averted the extent of the avalanche and lake with no room to spare, suggesting an element of good luck.

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Figure 4. TAPS south of the Alaska Range, highlighting several innovative design features of the TAPS, including the burial of the pipeline in some sectors (such as here, where the pipeline goes underground), the elevation of the pipeline in other sectors, passive ammonia cooling system to maintain the frozen permafrost, and the zig-zag pattern designed to absorb earthquake-caused deformation. Photo courtesy of Jeffrey Kargel.

A larger view of the full ASTER image acquisition is shown. Note the presence of unfrozen sediment-laden glacier meltwater of the glacial lake (cyan) north of the oil port and east of the city of Valdez.  The unfrozen state of the lake in mid-winter is a testament to the unusually warm January in Alaska.

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The upper image is an ASTER RGB false-color composite image draped onto the GDEM2 shaded relief map that shows the broader area.  The town of Valdez is visible along the eastern arm of the Valdez Arm.  Valdez Glacier, with its terminal lake (cyan), is visible northeast of the city. The lower image is an inset that shows the site of the avalanche in more detail.

This winter has been extremely mild in Alaska, enough for the record books, and the weather data point to the likely trigger of the avalanche. National Oceanic and Atmospheric Administration (NOAA) records indicate the January 2014 snowpack for the Valdez recording station was far below normal, while the amount of precipitation (rain or snow-water equivalent) received was more than double the January normal since 1972.  The huge avalanche was conditioned by three consecutive days of record high or record high minimum temperatures and then triggered by days of record anomalous rainfall.

January 2004 temperature records for the Valdez recording station. The almost horizontal lines are the averages for those dates (“normals”) over the period 1972-2014. January 2014 was twice as wet as normal, and about 6°F (3.3 °C) warmer than normal, but the day of the disaster and three preceding days broke multiple weather records in several parameters. Daily low temperatures (not shown) were also exceptional, with no freezing conditions in Valdez for the three nights prior to the avalanche, whereas normal lows are about 19 degrees for those dates.

January 2014 temperature records for the Valdez recording station. The almost horizontal lines are the averages for those dates (“normals”) over the period 1972-2014. January 2014 was twice as wet as normal, and about 6°F (3.3 °C) warmer than normal, but the day of the disaster and three preceding days broke multiple weather records in several parameters. Daily low temperatures (not shown) were also exceptional, with no freezing conditions in Valdez for the three nights prior to the avalanche, whereas normal lows are about 19 degrees for those dates.

A sequence of exceptional weather anomalies extend back to October.  That conditioning set the stage for the rainfall trigger to release the huge avalanche. The warm weather across most of Alaska—including an Arctic January in Kotzebue that experienced winter temperatures more typical of those in Portland, Oregon, is the other side of the coin that dealt the U.S. East, Midwest, and South a severe deep freeze.  Such extreme oscillations of weather are related to a deeply dipping jet stream and establishment of a days-long flow of saturated tropical air into the Valdez area. These conditions, particularly the strong meridional flow of air masses and “stuck” jet streams that resulted in prolonged extreme weather patterns, are thought to be increasing in frequency due to global warming, according to climate modeling by Jennifer Francis (Rutgers University) and colleagues.  The Arctic is warming more rapidly than the Tropics, which may be forcing changes in global circulation and weather patterns.

However, decadal variability caused by atmospheric and oceanographic “teleconnections” to the rest of the planet (El Niño/La Niña being the most famous example, and the Pacific Decadal Oscillation being the one most relevant to southern Alaska) are always causing climatic oscillations and sometimes extreme weather, so we cannot yet point definitively to climate change, as opposed to these oscillations, as the underlying cause of this event.  These climatic oscillations affect everything from the salmon fisheries to snowfall and rain patterns, so climatologists will have to look deeply at global warming, disappearing sea ice in the Arctic, and climate oscillations to find the ultimate answer to why Alaska’s weather has been so weird (and indirectly, why this mega-avalanche occurred), and how that relates to what is happening around the globe.

Figure 7. GOES-15 satellite image at 6.5 microns(a region of the thermal infrared that is absorbed by water vapor), portrayed as the temperature at the top of the water-vapor emitting region (clouds or humid air). Reds and yellows portray a very dry atmosphere, where emission of thermal infrared arises very deep in the atmosphere at high temperatures; blues indicate a moister atmosphere, and white and green an extremely moist atmosphere extending to very high altitudes having very low temperatures. The image was acquired 3:00 PM (local Alaska Time Zone) on 23 January 2014, the afternoon before the giant avalanche. A stream of extremely moist air arising in the northern Tropics—sometimes called the Pineapple Express—had been slamming into the Valdez and Keystone Canyon area (red square) for several days, thoroughly soaking the area. Valdez received over 11 inches of rain in the 12 days preceding the avalanche. Image rendered and made available by the Cooperative Institute for Meteorological Satellite Studies (CIMSS), University of Wisconsin – Madison, USA.

GOES-15 satellite image at 6.5 microns (a region of the thermal infrared that is absorbed by water vapor), portrayed as the temperature at the top of the water-vapor emitting region (clouds or humid air). Reds and yellows portray a very dry atmosphere, where emission of thermal infrared arises very deep in the atmosphere at high temperatures. Blues indicate a moister atmosphere, and white and green an extremely moist atmosphere extending to very high altitudes having very low temperatures. The image was acquired 3:00 PM (local Alaska Time Zone) on January 23, 2014, the afternoon before the giant avalanche. A stream of extremely moist air arising in the northern Tropics—sometimes called the Pineapple Express—had been slamming into the Valdez and Keystone Canyon area (red square) for several days, thoroughly soaking the area. Valdez received over 11 inches of rain in the 12 days preceding the avalanche. Image rendered and made available by the Cooperative Institute for Meteorological Satellite Studies (CIMSS), University of Wisconsin – Madison, USA.

The avalanche in Alaska cannot be blamed squarely on climate change, but it is another reminder that as climate changes, extreme weather may also be changing, and this impacts the well-being of people and critical infrastructure. Climate change and effects on natural hazards and disasters represents a moving target that must be re-examined by those planning the future, whether it is construction of major infrastructure or planning for disaster recovery. Climate change is not just a matter for the distant future, but it is ongoing now.

We thank the NASA Cryosphere Program, which funds our glacier and cryosphere related research, and the U.S.-Japan ASTER project, which provided the ASTER imagery.

Editor’s Note: Jeffrey Kargel is a hydrologist at the University of Arizona and for the Global Land Ice Measurements from Space project. This is his account of the research he did during the aftermath of a deadly flash flood in Nepal’s Seti River Valley to determine its cause. You can read more about the event here.

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Silt and gravel deposits trace the path of the 2012 hyperconcentrated slurry flood, which ravaged Kharapani village, shown here. Annotations show where people died and where they survived. Our research group has undertaken a detailed demographic and sociological investigation of the losses and survivors all along the devastated parts of the Seti River. The panel at lower right was a 1-year anniversary meet-and-greet commemoration, where we met survivors, media, and politicians still very much concerned about the disaster. (Photos courtesy of Jeffrey Kargel, University of Arizona.)

On May 5, 2012, I was attending a conference at ICIMOD (the Kathmandu-based International Centre for Integrated Mountain Development). I heard about the terrifying disaster that day. A flash flood—what geologists call a hyperconcentrated slurry because it was thick with suspended silt—had torn through some villages along the Seti River, in north-central Nepal, just north of the country’s second largest city, Pokhara. It was immediately recognized as a very deadly event, but the death toll—and a tally of those who remain missing but were clearly also killed—was not known exactly for several months. Seventy-two souls lost. Though not large on the scale of global disasters, this event was terrifying for the fact that it seemed to come from nowhere—literally from beneath a blue sky. Furthermore, there was no immediately evident cause. Nobody and no camera captured the whole event, but there were bits and pieces that had to be spliced together, and missing parts of the story had to be built from the ground up—literally from the rocks and sediment involved in the disaster.

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The source area for the avalanche of May 5, 2012. Annapurna IV is just off image to the upper left. The rocks here are layered metamorphosed sedimentary rocks deposited originally in the Tethys Sea before the Himalaya rose; the rock layers are now tilted up. Ice hangs precariously at the ridgeline, and apparently an icefall started the whole messy disaster. A dust cloud lingers from a small debris fall just moments after we first landed in Sabche Cirque 6 months after the disaster. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

Seeing that the disaster occurred at the foot of the Annapurna Range, within the Greater Himalaya, probably every expert’s first thought was “glacial lake outburst flood” (GLOF), because these were common in Nepal’s Himalaya, and the news accounts of the disaster event resembled accounts of GLOFs from other parts of the country.  It took me 10 minutes to examine recent satellite imagery enough to see that there were no lakes, at least not in the images I examined, that could have burst out like this.  So either there was a hidden glacial lake somewhere—maybe under the glacier ice—or a glacial lake developed very rapidly and then drained that tragic day, or—far more probable—this was not a GLOF at all.  It was, however, clearly a disaster that had its source in a high Himalayan amphitheatre-like bowl, a glacially-carved structure called the Sabche Cirque. This structure was rimmed by some of Nepal’s most famous, picturesque mountain peaks, including the storied, holy Machapuchare (the “fishtail” peak) and Annapurna IV, a 24,688-foot (7525 m) soaring metamorphic buttress of metamorphic rock.

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View of the avalanche deposit of rock and ice shed from Annapurna IV, which is just beyond the upper right corner. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

One of the most important pieces of information on the cause of the disaster was obtained from wingtip cameras mounted on a tiny 2-seater tourist plane.  The pilot, Captain Maximov, had observed what was obviously a giant avalanche—bigger and browner than any snow avalanche he had ever seen before; he then he saw a massive flood wave pouring down the Seti River valley.  It was evident immediately that this brown cloud of roiling airborne debris was connected to the trigger for the disastrous flood.

This distant view provided in the tourist plane’s video, in addition to later observations I was able to make from the Sabche Cirque itself, led to a confident sourcing of the brown cloud and the disaster’s trigger on a ridgeline near Annapurna IV.  Apparently part this ridge—probably initially the glacier ice— collapsed, dropping ice and rock over 3000 m almost vertically (about 10,000 feet) onto unconsolidated rock debris (glacial moraines and ancient glacial lake silts and gravels) resting unstably in the deep bowl of the Sabche Cirque.  Some of that loose debris was also swept up by the avalanche, and the mass flowed an additional 1,500 meters (about 5,000 feet) into the Seti River gorge.

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Ancient glacial lake sediments such as these in the Sabche Cirque were swept up by the avalanche and ingested both into the ground surge and airborne cloud, then ingested into the reservoir, which then burst forth onto unsuspecting people below.(Photo courtesy of Jeffrey Kargel, University of Arizona.)

The triggering avalanche—though enormous and bigger than almost any normal avalanche—was the easy part of the explanation of the disaster.  The hard part was identifying the source of the water, because there was no glacial lake or no known lake at all in the area.  Somewhere a large amount of water had been stored and then suddenly released. Speculation centered on water contained within unseen and unknown caves, or within the deep gorge of the Seti River, and last of all, possible subglacial lakes or lots of little ponds that acted like one big lake. This flood appeared to behave like a glacier lake outburst flood, and the news media can be pardoned for having assumed that it was. From that first day, I and other experts tried to counter the media view that it was a GLOF, but anyway, it was a lot of floodwater.

Since I was in Nepal, I immediately contracted for a helicopter to fly me and some colleagues over the Sabche Cirque. We observed directly evidence of the avalanche—boulders and dust and snow-like pulverized ice in a huge sheet, and streamers of debris emanating from the base of Annapurna IV to the head of the enormous Seti River gorge. We helicoptered over the glaciers and found some small ponds, but nothing that could explain the volume of water; and besides, the ponds were in the wrong place to have been strongly affected by Annapurna IV’s ice/rock avalanche. The pathway of the avalanche became ever clearer after post-disaster Landsat and ASTER images showed clear details of the avalanche deposits.

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The avalanche route through the upper gorge. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

Speculation was now focused toward the gorge. Could something have blocked it?  Well corroborated resident eyewitnesses interviewed by our team indicated that one to three weeks prior to the disaster, the Seti River had slowed to a mere trickle of clean water, unlike the usual turbid, sediment-laden “glacial milk.” (Seti means white, so it is the White River.)  These various observations and ideas had already started to coalesce when my assistant, Greg Leonard, observed a speck of change that had occurred in “before” and “after” ASTER satellite images.  We had a specific spot to look for a rockfall into the gorge.  Then looking at our helicopter-borne photography, we found it. It was indeed a fresh rockfall straight into the gorge, right at a place from which it appeared a backed-up reservoir had issued a flood. Furthermore, Greg showed that the gorge had experienced many smaller rockfalls or other erosional events over the previous decade, but this bigger one seemed to be fresh. The gorge now seemed the likeliest culprit, but at first it seemed difficult to comprehend how much water could be stored in the gorge behind a rockslide dam.

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Flattened forest blown down by the avalanche winds. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

In the days after the disaster, I examined amateur video of the event taken from Pokhara, a couple dozen kilometers downstream from the gorge. I watched as the flood reached Pokhara and as floating trees trunks poured over a dam. It provided the first best opportunity to measure the speed of the floodwaters and its depth and width, and thus measure the volume rate of flow and estimate the total flood volume. The flood came in waves, and the first wave alone was around a quarter of a million cubic meters in just a few minutes. There were about 27 waves in all over the next hours, according to eyewitnesses, so several million cubic meters overall.

At first it seemed a stretch for any one of the suggested water sources to explain the water volume, and this still is a part of the challenge to provide the full explanation of this event. Even my grandson, also intrigued as well as horrified by the disaster, brought his 7-year-old intellect to bear and suggested that it was friction that melted snow and ice that had tumbled off the peaks. Indeed, the conversion of gravitational potential energy to heat could have melted roughly a tenth of the falling snow and ice by the time it reached the Seti River. Nothing seemed quite sufficient; every potential source at first appeared an order of magnitude insufficient to explain the water volume. It seemed that all of the possible sources together might explain the floodwater volume.  Yet one source seemed to be definitely involved, and that was a rockslide-dammed reservoir in the gorge.

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A view of the gorges and also the distant peaks of the Sabche Cirque and the ancient glacial deposits in between. The avalanche entered the gorge from the upper right corner of the scene.

I returned with colleagues to the Sabche Cirque three more times, and we were able to land and set up camp and undertake detailed geological observations. The Sabche Cirque is a violent but beautiful place, with rockfalls, snow and ice avalanches, and flood dangers abounding, and evidence of big and recent geologic activity everywhere we walked or flew. We sampled and later chemically and mineralogically analyzed the dust fallout from Captain Maximov’s brown cloud, and linked it to the sediment deposited by the flood on the ravaged villages downstream. We analyzed the bedrock, the boulders of the avalanche, and searched for other evidence of floods and debris flows. That evidence is everywhere. However, the more we searched, the more it became evident that this was definitely not a GLOF, but was caused by a rockslide into the Seti River gorge, formation of an impoundment reservoir over a several week period due to damming of spring snow and ice melt, and then the final triggering event of the mighty rock and ice avalanche off Annapurna IV. On our most recent trip we used a laser device to determine the depth and width of the gorge and discovered that it is so immense that it alone might account for the required water volume.

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Our first view of the rockslide that initially dammed the Seti River some weeks prior to May 5, 2012, and set the stage for the deadly terror. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

Although this was a terrifying and deadly event, by geologic standards it was not particularly huge. The death toll was due foremost to people living in harm’s way on the lowest terrace and even on the lowest floodplain. Our findings do not bode well for the future of the small settlements scattered along the riverside, and there would seem to be a strong case for resettlement.

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Another devastated area, where there were losses and survivors. A year after the disaster, we were surprised to see a woman living in a house that had barely escaped destruction. Her husband was a river worker. Cattle were grazing nearby. Survivors told harrowing and heart-breaking stories of their tragic losses. (Photos courtesy of Jeffrey Kargel, University of Arizona.)

ACKNOWLEDGMENTS.  This sequence of events was pieced together from many data sources, and many people were involved, among them my colleagues and myself, but also Captain Maximov, local villagers, landslide blogger David Petley and his associates; research staff and my field assistants from ICIMOD, especially Sharad Joshi; my other Nepalese colleagues, including Dr. Dhananjay Regmi and Dr. Lalu Poudel; our chief climber, JB Rai and his Sherpa assistants; and two doctoral students, Khagendra Poudel and Bhabana Thapa, who are investigating the geomorphology and sociology of the disaster. I also need to give special thanks to my tireless assistant, Greg Leonard, who was the prime satellite image analyst as well as my chief field assistant.  Finally, I express gratitude to the NASA/USAID SERVIR Applied Sciences Team,  NASA’s Cryosphere Program, and the USAID Climber Science Program, who funded different aspects and phases of this work, and the U.S.-Japan ASTER project, which provided the ASTER imagery. This work will be presented in more complete detail within an upcoming peer-reviewed scientific publication.

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A mosaic of images showing the rockslide area in the foreground in the glacial sediments and avalanche route in the background. (Photo courtesy of Jeffrey Kargel, University of Arizona.)

 

Siberia 2012: Final Thoughts

August 15th, 2012 by Joanne Howl

Greenbelt, MD

84°F High   74° F low   Sunny

The transition from a remote-area scientific expedition to everyday life comes fast and hard.  Even though the flight from Tura to Baltimore consumes over 24 hours, those are the last slow moments that the scientist will experience.  The moment the aircraft touches down, the race begins.  It is a race not only to recover a daily routine that has become foreign while in the field, but also a race to catch up on the set-aside responsibilities of family and friends, and everyday life.

The scientists relax on the Kochechum River on the last day of the Siberia 2012 Expedition. The last day was long, but peaceful. When they arrived in Tura, they heard the news that the rivers were so low that ships that supply the town could not navigate the rivers, so many supplies in the town were running low. From back to front: Pasha Oskorbin, Guoqing Sun, Ross Nelson.

On the Embenchime, life was simple and direct.  In Siberia all efforts were focused on food, shelter, transportation, and making scientific observations and collecting data.  But in America, life is fast, distracting and complex.  From the moment of return, there are bills to pay, meetings to attend, past due work to accomplish, and so much more. The clamor can be overwhelming.   It takes several weeks to emerge from the transitional hubbub.

Our scientists left the dry Siberian rivers on July 22, and the American contingent returned home shortly after.  Jon Ranson and Ross Nelson stepped off the airplane from Russia late on July 24, and were back at their office jobs early the next day.  Gouqing Sun took a short amount of personal time in China to visit relatives before returning to America about a week later.  Now, nearly three weeks later, the scientists finally have a moment to recap their days on the Embenchime.  Dr. Jon Ranson and Dr. Slava Kharuk send the following closing thoughts.

From Dr. Jon Ranson:

Our travels for the 2012 Siberia expedition are now complete.  Everyone has returned to their families in Russia or the United States.  Life as we know it is returning to normal.  I have lots of memories (and field books full of observations) of the many faces of the larch forest in Siberia.  But the common face of the forest can be summed in one word: change.

Whether viewed from helicopter, boat or on foot, huge areas of forest show the effects of fires.  Some fires are recent, but most burned a couple of decades in the past. Because of how remote those forests are, and given the absence of people, most of these fires were likely caused by lightning.  In many places the larch forest regrows, in some places it does not.  We thought we understood how larch forests regenerated, but this change we’ve seen – some stands do not appear to be regenerating – certainly calls for study.

One of the changes observed in the larch forest was the significant amount of burned area. Fires appear to be returning to these forests more frequently than they have in the past. The samples collected on this expedition (in the foreground) will help quantify the fire-return intervals in the Siberian larch forest.

In any given area, there has been a trend for less time between fires – the fire return interval is changing.  Professor Kharuk’s additional analysis on the fire scar samples will quantify this trend.   Change is also occurring in the form of soil slumps and landslides as thawing permafrost allows whole hillsides of forest to slide down into the river.   More subtle changes are the accelerated growth of individual trees in this area from the warming climate.  Our field data should reveal and help quantify those changes.  Our task ahead is to develop methods that take what we are learning about the larch forests in these central Siberia expeditions and apply it to the whole of the forest with aircraft and satellite remote sensing.  Then we will know better the extent and the consequences of these changes.

This is our ninth joint expedition with our Russian colleagues in the Siberian forests.  These expeditions take a lot work in planning, in executing the expedition on-site, and then in analyzing the data.  Success depends in large part on uncontrollable things like airline schedules, weather and durability of equipment.  But the primary key to success is the dedication of the expedition team – each scientist must fully commit themselves to stay focused on our goals and to overcome whatever challenge comes our way.

The joint scientific effort between NASA and Sukachev has endured for over two decades mostly because of the commitment of the scientists involved.  Everyone, (including our sponsors) understands the scientific importance of gaining firsthand information about these forests, and everyone is dedicated to making the most of this opportunity.  In addition I think we all have a sense that these expeditions, while challenging, can be seen as an adventure, and are essential to help us to be “grounded” in our science when back at the office.

We appreciate everyone who has looked in on this blog, and who have followed our personal and scientific journey on the Embenchime this year.  There is much more work to do in this region – and we will return next year.  In 2013, we will not only be making ground measurements, but we will also be flying multiple instruments (lidars, and hyperspectral and thermal cameras) to help us better quantify the changes in the larch forest.  We hope that you will come along with us, again, via the Earth Observatory.

 

From Dr. Slava Kharuk:

This was our third remote river expedition with NASA’s scientists to larch dominated communities. We crossed larch forests by boating on Embichimo River. Helicopter and boat are the only means to get the study area. The Embechimo is a consequence of rapids, rough waters and “lake-like” surfaces, with underwater boulders which lie in ambush to crush boat engines. Our only hopes for relief were additional water from tributary rivers.

The 2012 Siberia crew at the end of the expedition. From left to right: Guoqing Sun, Ross Nelson, Jon Ranson, Slava Kharuk, Sergei Im, Pasha Oskorbin. This team plans to return to the region in 2013, bringing new instrument technology to help collect data required to understand the changes which are occurring in the larch forests of Siberia.

But those tributaries were almost dried out: hot!  It has been unusually hot … and so many forest fires, too. “Dry” thunderstorms caused fire ignitions over a millions hectares. The landscapes along the route were regenerating burns of different post-fire ages.  We saw successions from seedlings embedded into “battle field” of mortal trees up to mature forests. The history of these “battles” was imprinted in burnmarks on the surviving and dead boles.

Warming-induced fire frequency increase may convert Siberian taiga from the sink to the source of carbon dioxide (at least at short time intervals). Also, fires promote larch domination, since conquered species are less fire-resistant. Warming also increases seasonal permafrost thawing depth and soil drainage, prolonging vegetation period, and, consequently, promotes an increase in larch growth.  White-hot Arctic Circle sun irradiated energy is similar to Amazonian sun during polar days. But warming also provides opportunities for the “southern species” (Siberian pine, spruce, fir, birch, aspen) to migrate into larch habitat.

In a changing climate, larch forests contain a number of challenging questions.  To answer these questions, expedition studies and in-lab analysis are needed.

Since the expedition has passed, my dreams are still about larch forests, fire burns, moose and caribou watching with wide-open eyes the approaching expedition boats… and a nightmare of rough waters, rapids and hidden underwater boulders.  We will return once again, next year.

Notes from the Field