Outdoors, Science

Glacial Lake Outburst Flood (GLOF) Investigation at Bear Glacier during 2017 Summer Season

Bear Glacier Glacial Outburst Flood Camera Installation 2017. Image Courtesy of Kenai Fjords National Park.

Seward, AK –Bear Glacier is located on the Kenai Peninsula southwest of Resurrection Bay and Seward, Alaska. The lower (proglacial) lake in front of Bear Glacier is a popular recreation area in Southern Alaska for kayaking, sight-seeing, surfing and camping.

Glacial lake outburst floods occur when water trapped by glacier ice rapidly drains through a variety of flow paths down-glacier. An ice-dammed lake in the Northeastern trunk of Bear Glacier has caused multiple outburst floods in previous years. Past observations tell us the lake fills throughout the course of the summer and releases during the fall. When the release occurs quickly, it causes a flood event inundating the lower, proglacial lake; some years the water drains slowly without noticeable impacts. Witness accounts during previous Bear Glacier flood events suggest water level can increase at least 1-2 meters within the proglacial lake and can be accompanied by large calving events at the face of the glacier.

In June 2017, Kenai Fjords National Park installed two time-lapse cameras, one at the ice dammed lake above Bear Glacier and one at the proglacial lake below the terminus. The cameras collect and email photos that provide a visual account of the water level in the lakes as they fluctuate. A pressure transducer installed in the proglacial lake collects precise water depth and temperature data which can be correlated with the time-lapse photography to assess the magnitude and time-scale of Bear Glacier’s outburst floods.

Although this may be a one-time study, this information is being gathered in hopes of better understanding the natural processes associated with Bear Glacier’s hydrology and outburst flood events.

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Kenai Fjords reminds visitors that glaciers are a dynamic natural force that are by definition in a constant state of change.  People should always use caution when playing, working or traveling around glaciers. Ice falls, calvings, collapses and outburst floods can and do occur without warning.

Photos of the ice-dammed lake (IDL) from June 10, 2017 and September 5, 2017, respectively. Although there is more ice earlier in the season, it melts and along with snow melt and rain, contributes to the lake filling during the summer. Photos Courtesy of Kenai Fjords National Park.

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