Wednesday, October 27, 2021

Caldera glimpse with decreased snowcover

Our most-recent fieldwork at Kilimanjaro summit was in February 2020, as the global pandemic began. Since then the mountain has been unusually quiet, with many guides and porters unemployed. They are as anxious as we are to get back up the mountain! Although satellite imagery allows us to assess some changes on the mountain, it is no substitute for on-site measurements and observations. Our reliable instrumentation on the Northern Icefield was functioning 18 months ago, yet the current status is unknown.

The image above was acquired by ESA's Sentinel-2 two days ago, revealing perhaps the least snowcover in several years. Such a view is especially valuable, as distinguishing between snow and ice on imagery is difficult. Clouds of course also complicate interpretation, and in this case case there are scattered clouds visible over the Northern Icefield's northern remnant, within the Breach on the west side, and over low-elevation portions of the southern glacier remnants. On visible portions of the south side, residual snow is estimated to comprise roughly half of the bright patches (i.e., non-glacier).

Noteworthy changes apparent in this image include on-going shrinkage of the Furtwängler Glacier (see above). The extent of south-side glaciers has clearly decreased, even acknowledging residual snowcover. At the Northern Icefield, the east end appears to have experienced the greatest change, due generally-thinner ice and a less-linear margin. In addition, several locations suggest that areas of anomalous geothermal heat are involved with ice loss, an ablation mechanism we have documented elsewhere at the summit. Further information on these new features will hopefully be forthcoming soon from Tanzanian collaborators.

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