Thursday, November 12, 2020

Seasonal change

Snowcover within the Kibo caldera may have reached an annual minima last week. The two-image Sentinel-2 timelapse above shows the same area, five days apart.

The mostly cloud-free image on 4 November depicts the largest extent of snowfree area for calendar year 2020. Nonetheless, note the extensive snowcovered area east of the Northern Icefield and north of Reusch Crater; this was evidently an area of higher accumulation during the previous wet seasons. South of Reusch Crater, white areas within the caldera are all patches of snow - with the exception of one remaining fragment of Furtwängler Glacier, the east-west oriented body just south of the extensive snowfree area. On the caldera's south side, snowcover blankets the south-southwest facing slope and delineates the rim, closely paralleling the trail from Stella Point to Uhuru Peak. Encompassed within this area are the upper fragments of Kersten and Deckens Glaciers, with less-continuous snow around the Rebmann Glacier. Below the upper south-side glaciers is a steep, 100-150 m band without snow, then patchy snow and the snowcovered lower fragments of the Kersten and Deckens Glaciers.

Snow blankets the entire upper portion of the mountain on 9 November, as visible in the second image (despite a thin cloud veil). This snowfall event is "right on schedule" in terms of the precipitation climatology for high elevations of Kilimanjaro. This would be a fascinating time to be up there, for a survey of snow depth and spatial variability...

Sunday, October 25, 2020

Fires extinguished, snowcover continues to decrease

I hear from friends in Mweka that wildfires on the mountain are now out, thanks both to some rain, and hard work by personnel. They burned quite close to the Mweka (descent) trail, just above the upper forest line, a zone which has been severely impacted by fires and climate change in recent decades (see Andreas Hemp reference within this link). A helicopter pilot from Kenya was able to provide valuable assistance to firefighters for several days.

Today's satellite image - and that of 20 October - shows considerable cloud cover on the mountain, as expected at this time of year. A "hole" in the clouds does reveal the caldera's west side, and much of the Breach, to now be snowfree.

The next clear view of the mountain will be posted here. Will any seasonal snow persist to the next period of accumulation? Stay tuned!

Thursday, October 15, 2020

Serious wildfires continue [updated]

This morning's Sentinel-2 image of Kilimanjaro reveals the seriousness of fires burning since Sunday, high on the mountain (bands 12, 11, and 4). Reports suggest the fire was started accidentally along the Marangu Route. Early reports from TANAPA expressed premature optimism that "the fire is already under control" (14 Oct. via @tzparks), yet Minister of Natural Resources and Tourism, Hamisi Kigwangalla, is quoted in the NY Times today:  "the task is harder and bigger than it is thought to be".

On the false color image above, note the Reusch Crater. Snow and ice appear royal blue, with burning areas in yellow-red. This is a very serious, extensive fire! Smoke is visible being blown westward from the fires, burning at an elevation above 3000 m. The dominant vegetation type at this level is giant heather (Erica excelsa), which ecologist Andreas Hemp describes as "an obvious fire sign" which "enhances the fire risk, as even fresh Erica wood burns well". As highlighted in a UNEP posting based on Hemp's work, "nearly 15% of Kilimanjaro’s forest cover was destroyed by fire since 1976 and was replaced by Erica bush which extended its total area by 5km2 (mainly downslope)."

The upper portion of the popular Marangu Route is shown in green, passing Horombo Huts where some fire damage may have occurred. One updated account today (here) quotes Minister Kigwangalla as saying that yesterday's rebound "destroyed the Horombo Tourist Camp, including 12 huts, two toilets, and solar equipment". The mountain's primary descent route past Barafu Camp is also shown, appearing to be threatened by both fire and smoke.

We await first-hand reports from the mountain, and welcome any additional information.

[UPDATE 10/16:  Our friend Timba (Travel Consultant in Moshi) sent a link depicting Carbon Monoxide concentration, via the Earth website. Although the screenshot below does not show the data well, note the value for Kilimanjaro of 13,116 parts per billion by volume (high enough to cause chronic problems with long-term exposure - from CO alone).]


Tuesday, September 15, 2020

Processes in opposition

Ablation of seasonal snowcover continues at Kibo's summit, while hints of the forthcoming short rain season are becoming evident. The Sentinel-2 image above shows both continuing ablation since the end of August (see previous posts), and a dusting of new snow on southeastern slopes. This is also a nice illustration of how localized snowfall can be on the mountain.

Light accumulating snowfall is common at this time of year, as is its subsequent ablation within a few days. These opposing processes are especially critical for the glaciers as the dry season concludes, because albedo reaches an annual minimum while temperature, humidity, and solar radiation are all increasing.

In today's image (not shown), partially obscured by clouds, the dusting of snow seen above has completely ablated, and snowcover within the caldera is patchier yet.

While it appears that areas of snow will endure the dry season this year, failure of the short rains - or even a delayed onset - might yet ablate much of the lingering summit snow.

Wednesday, September 9, 2020

What Will Gadd learned on top of Kilimanjaro

Red Bull today released a fantastic new Will Gadd film, shot with a full crew during our pre-COVID February trip. The finished product (45 minutes) is about extreme sport, but also about the science of Kilimanjaro glaciers and climate change; it is well worth watching.

Will was a joy to work with - as eager to learn and share knowledge as he is to climb ice - and clearly articulates the responsibility we all have to reduce our carbon impact. Red Bull deserves major credit for broadening the scope of their productions. And, the stuff is tasty!

Director Tom Beard and the KEO Films crew did a wonderful job of editing, and eagerly accepted ideas to insure an accurate result.

Access the film here:  <> or here.


Wednesday, September 2, 2020

31 August snowcover

Snowcover continued to decrease during the last 5 days of August, as the image below reveals relative to that from 26 August (previous post). Change appears most evident in the northwest corner of the caldera. Nonetheless, the extent of snow at the summit remains more than average - with perhaps two months remaining in the extended dry season.

Tourism on the mountain remains minimal, as the new Coronavirus pandemic continues. For example, the Machame register book shows only 58 climbers departing for the normally-busy months of July and August.

Our friend Simon Mtuy and a large SENE team have been assisting in a large clean-up operation. Over just two days, SENE staff collected 45 kilos of trash from the Machame Camp area. Simon reports that this week there will be 400 crew from 16 companies helping in the clean-up, which will include the Western Breach route and the Crater Camp area. Asante sana!


Monday, August 31, 2020

Snowcover at the end of August

Snowcover in the caldera has been decreasing through August, and is now at roughly 75% by area. The image above was acquired by Sentinel-2 on the 26th. Although it now appears possible to reach Stella Point without ascending on snow, considerable snow remains in some places, such as to the east of the Northern Icefield.

During the boreal summer months of June-August, when the sun is in the northern hemisphere, less solar radiation is received on any slope inclined to the south. Note the extent of snowcover remaining on the mountain's southern slopes (above). This
area coincides with where the Southern Icefield used to exist - illustrated below during Walter Mittelholzer's flight over the mountain in January 1930. Whereas most of the white area in 1930 is snow over glacier ice, very little ice remains on the south side in 2020.

(Preservation of seasonal snow on the south side is not solely a function of aspect. The spatial pattern of snowfall on the mountain between November 2019 and June 2020 is not known (and was likely not uniform), and snowcover retention is also governed by the s
easonal distribution and extent of cloud cover.)

Below: Mittelholzer's Fokker F.VIIb-3m "Switzerland" refueling enroute to Kilimanjaro [credit].