Kibo 2022 Dry Season begins

Throughout eastern Africa the dry season is getting underway, a period of 4-5 months with minimal precipitation. June typically begins with complete snowcover on Kilimanjaro, resulting from the March-May rainy season, which in some years supplements January snowfall events as well as snow deposited during the November-December short rains. With reduced cloud cover and lower temperatures on the mountain during the dry-season months, snow gradually sublimates and melts. This annual cycle of snowcover was roughly defined by the late 19th century:

Although Kilimanjaro lies near the equator the extent of its ice and snow varies with the season. The southern summer (December to May) is also the rainy season in the Kilimanjaro region, and it is then that the accumulations of ice and snow are greatest. In the southern winter (June to November) there is a comparative dearth of moisture, the snowfall is proportionately slight, and the process of melting goes on rapidly; hence, by the end of the season, the accumulations of ice and snow are at their smallest.
    Hans Meyer, Across East African Glaciers (1891)

Snow currently blankets only about half of the summit caldera, and only the southern flanks - as illustrated on the satellite image above, from last week (2 June). Within the caldera, this pattern of accumulation has remained quite consistent through the 2022 long rains. More noteworthy is that accumulation is clearly less than normal. Compare this year's snowcover with that of 2020 and 2018 in these images:

In a larger spatial context, snowcover on Kilimanjaro following the long rains is illustrative of the "current extreme, widespread, and persistent multi-season drought (1)" affecting East Africa, particularly in Kenya, Ethiopia, and Somalia. The figure below depicts only the most-recent wet season precipitation, as the satellite images also reflect. A joint statement by the World Meteorological Organization, UN Food and Agriculture Organization, and others states that "The 2022 March-May rainy season appears likely to be the driest on record, devastating livelihoods and driving sharp increases in food, water, and nutrition insecurity" (1). In addition, East African air temperatures have been higher than normal, and these are forecast to continue through the forthcoming dry season.

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The current drought to the north of Kilimanjaro is both a direct and indirect consequence of climate change, and climate variability. Factors include a multiyear La Niña event (2), a longterm decrease in Long rains precipitation, more intense and severe extreme events, as well as changing large-scale patterns of convection and subsidence, driven by Sea Surface Temperature (SST) anomalies in the Indian Ocean.

Decreased snowcover on Kilimanjaro during the 2022 dry season will hasten ablation of the glaciers. Comparing the current satellite image with those of snowier years dramatically illustrates the role of snowcover in determining the reflectivity of solar radiation. Without snow, the dark volcanic surface absorbs radiation, heats up, and radiates longwave radiation to the air and adjacent ice. Kilimanjaro's summit is 5000 m above the drought-stricken plains below (primarily north of the mountain), providing information on the climate system from the mid-troposphere. These shrinking glaciers serve as a constant reminder of the importance of precipitation to human and natural systems.