At first sight, Kilimanjaro’s glaciers look like nothing more than big smooth piles of slightly monotonous ice. On second sight they pretty much look like this too. Yet there’s much more to Kili’s glaciers than meets the eye, for these cathedrals of gleaming blue-white ice are dynamic repositories of climatic history – and they could also be providing us with a portent for impending natural disaster.
You would think that with the intensely strong equatorial sun, glaciers wouldn’t exist at all on Kilimanjaro. In fact, it is the brilliant white colour of the ice that allows it to survive as it reflects most of the heat. The dull black lava rock on which the glacier rests, on the other hand, does absorb the heat; so while the glacier’s surface is unaffected by the sun’s rays, the heat generated by the sun-baked rocks underneath leads to glacial melting.
As a result, the glaciers on Kilimanjaro are inherently unstable: the ice at the bottom of the glacier touching the rocks melts, the glaciers lose their ‘grip’ on the mountain and ‘overhangs’ occur where the ice at the base has melted away, leaving just the ice at the top to survive. As the process continues the ice fractures and breaks away, exposing more of the rock to the sun… and so the process begins again. The sun’s effect on the glaciers is also responsible for the spectacular structures – the ice columns and pillars, towers and cathedrals – that are the most fascinating part of the upper slopes of Kibo.
Why haven’t Kilimanjaro’s glaciers melted away?
One would have thought that, after 11,700 years of this melting process, (according to recent research, the current glaciers began to form in 9700BC) very little ice would remain on Kilimanjaro. The fact that there are still glaciers is due to the prolonged ‘cold snaps’, or ice ages, that have occurred down the centuries, allowing the glaciers to regroup and reappear on the mountain. According to estimates, there have been at least eight of these ice ages, the last a rather minor one in the fifteenth and sixteenth centuries, a time when the Thames frequently froze over and winters were severe. At these times the ice on Kilimanjaro would in places have reached right down to the tree line and both Mawenzi and Kibo would have been covered. At the other extreme, before 9700BC there have been periods when Kilimanjaro was completely free of ice, perhaps for up to twenty thousand years.
Why is it called ‘Kilimanjaro’?
Despite extensive studies into the etymology of the name Kilimanjaro (note it’s not spelt ‘Kilamanjaro’, though you’d be amazed at how many people spell it that way), nobody is sure where it comes from or what exactly it means.
When looking for the name’s origin, it seems only sensible to begin such a search in one of the local Tanzanian dialects, and more specifically, in the language spoken by those who live in its shadow, namely the Chagga people. True, the name Kilimanjaro bears no resemblance to any word in the Chagga vocabulary; but if we divide it into two parts then a few possibilities present themselves. One is that Kilima is derived from the Chagga term kilelema, meaning ‘difficult or impossible’, while jaro could come from the Chagga terms njaare (‘bird’) or jyaro (‘caravan’). In other words, the name Kilimanjaro means something like ‘That which is impossible for the bird’, or ‘That which defeats the caravan’ – names which, if this interpretation is correct, are clear references to the sheer enormity of the mountain.
Whilst this is perhaps the most likely translation, it is not, in itself, particularly convincing, especially when one considers that while the Chagga language would seem the most logical source for the name, the Chagga people themselves do not actually have one single name for the mountain! Instead, they don’t see Kilimanjaro as a single entity but as two distinct, separate peaks, namely Mawenzi and Kibo. (These two names, incidentally, are definitely Chagga in origin, coming from the Chagga terms kimawenzi – ‘having a broken top or summit’ – and kipoo – ‘snow’ – respectively.)
Assuming Kilimanjaro isn’t Chagga in origin, therefore, the most likely source for the name Kilimanjaro would seem to be Swahili, the majority language of the Tanzanians. Johannes Rebmann’s good friend and fellow missionary, Johann Ludwig Krapf, wrote that Kilimanjaro could either be a Swahili word meaning ‘Mountain of Greatness’ – though he is noticeably silent when it comes to explaining how he arrived at such a translation – or a composite Swahili/Chagga name meaning ‘Mountain of Caravans’; jaro, as we have previously explained, being the Chagga term for ‘caravans’. Thus the name could be a reference to the many trading caravans that would stop at the mountain for water. The major flaw with both these theories, however, is that the Swahili term for mountain is not kilima but mlima – kilima is actually the Swahili word for ‘hill’!
The third and least likely dialect from which Kilimanjaro could have been derived is Masai, the major tribe across the border in Kenya. But while the Masai word for spring or water is njore, which could conceivably have been corrupted down the centuries to njaro, there is no relevant Masai word similar to kilima. Furthermore, the Masai call the mountain Oldoinyo Oibor, which means ‘White Mountain’, with Kibo known as the ‘House of God’, as Hemingway has already told us at the beginning of his – and our – book. Few experts, therefore, believe the name is Masai in origin.
ther theories include the possibility that njaro means ‘whiteness’, referring to the snow cap that Kilimanjaro permanently wears, or that Njaro is the name of the evil spirit who lives on the mountain, causing discomfort and even death to all those who climb it. Certainly the folklore of the Chagga people is rich in tales of evil spirits who dwell on the higher reaches of the mountain, and Rebmann himself refers to ‘Njaro, the guardian spirit of the mountain’; however, it must also be noted that the Chagga’s legends make no mention of any spirit going by that name.
And so we are none the wiser. But in one sense at least, it’s not important: what the mountain means to the 35,000 who walk up it every year is far more meaningful than any name we ascribe to it.
Where is Kilimanjaro?
Kilimanjaro sits on the northern border of Tanzania, overlooking Kenya, and just over 200 miles south of the Equator. The area is not particularly mountainous; indeed, the nearest mountain to Kilimanjaro is Mount Meru, over 60km away to the south-west.
Kilimanjaro geology
Rising 4800m above the East African plains, 270km from the shores of the Indian Ocean and measuring up to 40km across, Kilimanjaro is a bizarre geological oddity, the tallest freestanding mountain in the world and one formed, shaped, eroded and scarred by the twin forces of fire and ice. It is actually a volcano, or rather three volcanoes, with the two main peaks, Kibo and Mawenzi, the summits of two of those volcanoes. The story of its creation goes like this:
The Rift Valley
About three-quarters of a million years ago (making Kilimanjaro a veritable youngster in geological terms) molten lava burst through the fractured surface of the Great Rift Valley, a giant fault in the earth’s crust that runs through East Africa (actually, Kilimanjaro lies 50 miles from the East African Rift Valley along a splinter running off it, but that need not concern us here). The huge pressures behind this eruption pushed part of the Earth’s crust skywards, creating the Shira volcano, the oldest of the volcanoes forming the Kilimanjaro massif. Shira eventually ceased erupting around 500,000 years ago, collapsing as it did so to form a huge caldera (the deep cauldron-like cavity on the summit of a volcano) many times the size of its original crater
The formation of Kibo and Mawenzi
Soon after Shira’s extinction, Mawenzi started to form following a further eruption within the Shira caldera. Though much eroded, Mawenzi has at least kept some of its volcanic shape to this day. Then, 460,000 years ago, an enormous eruption just west of Mawenzi caused the formation of Kibo. Continual subterranean pressure forced Kibo to erupt several times more, forcing the summit ever higher until reaching a maximum height of about 5900m. A further huge eruption from Kibo 100,000 years later led to the formation of Kilimanjaro’s characteristic shiny black stone – which in reality is just solidified black lava, or obsidian. This spilled over from Kibo’s crater into the Shira caldera and around to the base of the Mawenzi peak, forming the so-called Saddle. Later eruptions created a series of distinctive mini-cones, or parasitic craters, that run in a chain south-east and north-west across the mountain, as well as the smaller Reusch Crater inside the main Kibo summit. The last volcanic activity of note, just over 200 years ago, left a symmetrical inverted cone of ash in the Reusch Crater, known as the Ash Pit, that can still be seen today.
Kilimanjaro’s glaciers
Today, Uhuru Peak, the highest part of Kibo’s crater rim and the goal of most trekkers, stands at around 5895m. The fact that the summit is around five metres shorter today than it was 450,000 years ago can be ascribed in part to some improved technology, which has enabled scientists to measure the mountain more accurately; and in part to the simple progress of time and the insidious glacial erosion down the millennia. These glaciers, advancing and retreating across the summit, created a series of concentric rings like terraces near the top of this volcanic massif on the western side. The Kibo peak has also subsided slightly over time, and about one hundred thousand years ago a landslide took away part of the external crater, creating Kibo Barranco or the Barranco Valley (home to one of the mountain’s more popular campsites). The glaciers were also behind the formation of the valleys and canyons, eroding and smoothing the earth into gentle undulations all around the mountain, though less so on the northern side where the glaciers on the whole failed to reach, leaving the valleys sharper and more defined.
Is Kilimanjaro now an extinct volcano?
While eruptions are unheard of in recent times, Kibo is classified as being dormant rather than extinct, as anybody who visits the inner Reusch Crater can testify. A strong sulphur smell still rises from the crater, the earth is hot to touch, preventing ice from forming, while occasionally fumaroles escape from the Ash Pit that lies at its heart.
What does Kilimanjaro look like?
Kilimanjaro is not only the highest mountain in Africa, it’s also one of the biggest volcanoes on Earth, covering an area of approximately 388,500 hectares.
The summits of Kilimanjaro
Within this 388,500-hectare area are three main peaks
The Kibo summit
The Kibo summit is the best preserved crater on the mountain; its southern lip is slightly higher than the rest of the rim, and the highest point on this southern lip is known as Uhuru Peak. At 5895m, this is highest point in Africa and the goal of just about every Kilimanjaro trekker. Kibo is also the only one of the three summits which is permanently covered in snow, thanks to the large glaciers that cover much of its surface.
Kibo is also the one peak that really does look like a volcanic crater; indeed, there are not one but three concentric craters on Kibo.
Within the inner Reusch Crater (1.3km in diameter) one can still see signs of volcanic activity, including fumaroles, the smell of sulphur and a third crater, the Ash Pit, 130m deep by 140m wide
The outer, Kibo Crater (1.9 by 2.7km), is not a perfect, unbroken ring. There are gaps in the summit where the walls have been breached by lava flows; the most dramatic of these is the Western Breach
Many climbers used to gain access to the summit each year through this breach, though that route has been closed since 2006 due to a rockfall on the route that killed four climbers.
Perhaps the most important feature of Kibo, however, is that its slopes are gentle. This feature means, of course, that trekkers as well as mountaineers are able to reach the summit.
Mawenzi
Mawenzi is the second highest peak on Kilimanjaro. Seen from Kibo, Mawenzi looks less like a crater than a single lump of jagged, craggy rock emerging from the Saddle (see ‘Other features of Kilimanjaro’ below). This is merely because its western side also happens to be its highest, and hides everything behind it.
Walk around Mawenzi, however, and you’ll realize that this peak is actually a horseshoe shape, with only the northern side of the crater having been eroded away. Its sides too steep to hold glaciers, there is no permanent snow on Mawenzi, and the gradients are enough to dissuade all but the bravest and most technically accomplished climbers.
Mawenzi’s highest point is Hans Meyer Peak at 5149m but so shattered is this summit, and so riven with gullies and fractures, that there are a number of other distinctive peaks including Purtscheller Peak (5120m) and South Peak (4958m). There are also two deep gorges, the Great Barranco and the Lesser Barranco, scarring its north-eastern face
The Shira Ridge
The oldest and smallest summit on Kilimanjaro is known as the Shira Ridge, and lies on the western edge of the mountain. This is the least impressive peak, being nothing more than a heavily eroded ridge, 3962m tall at its highest point, Johnsell Point. This ridge is, in fact, merely the western and southern rims of the crater formed by the original volcanic eruption (see the geology page for more information).
Other features on Kilimanjaro
Separating Kibo from the second peak, Mawenzi, is the Saddle, at 3600ha the largest area of high altitude tundra in tropical Africa. This really is a beautiful, eerie place: a dusty desert almost 5000m high, featureless except for the occasional parasitic cone dotted here and there, including the Triplets, Middle Red and West Lava Hill, all running south-east from the south-eastern side of Kibo.
These are just some of the 250 parasitic cones that are said to stand on Kilimanjaro.Few people know this, but Kilimanjaro does actually have a crater lake. Lake Chala (aka Jala) lies some 30km to the south-east, and is said to be up to 2.5 miles deep.
The Shira Plateau is a large, rocky plateau, 6200ha in size, that lies to the west of the Kibo summit (ie between Kibo and the Shira Ridge). It is believed to be the caldera of the first volcanic eruption (a caldera is a collapsed crater) that has been filled in by lava from later eruptions which then solidified and turned to rock.
The paths on Kilimanjaro
Look down at Kilimanjaro from above and you should be able to count seven paths trailing like ribbons up the sides of the mountain. Five of these are ascent-only paths (ie you can only walk up the mountain on them and are not allowed to come down on these trails); one, Mweka, is a descent-only path, and one - the Marangu Route - is both an ascent and descent trail.
At around 4000m these trails meet up with a path that loops right around the Kibo summit. This path is known as the Kibo Circuit, though it’s often divided into two halves, known as the Northern and Southern circuits.
From here, three further paths lead up the slopes to the summit itself. For a brief description of the trails, and a look at their relative merits, follow this link to our Routes up Kilimanjaro page.
For further details, check out the full descriptions of each in the book, with carefully drawn maps and detailed information on each route. Note that some trekking agencies vary the routes slightly, particularly on the Shira Plateau, but any agency worth its salt will provide you with a detailed itinerary, enabling you to check exactly which path you will be taking each day.
Weather on Kilimanjaro
Kilimanjaro is big enough to have its own weather pattern. The theory behind this pattern is essentially very simple. Strong winds travel across the oceans, drawing moisture up as they go. Eventually they collide with a large object – such as a mountain like Kilimanjaro. The winds are pushed upwards as they hit the mountain slopes, and the fall in temperature and atmospheric pressure leads to precipitation or, as it’s more commonly called, snow and rain.
The ‘trade’ and ‘anti-trade’ winds of Kilimanjaro
In one year there are two rain-bearing seasonal winds buffeting Kilimanjaro. The south-east trade wind bringing rain from the Indian Ocean arrives between March and May. Because the mountain is the first main obstacle to the wind’s progress, and by far the largest, a lot of rain falls on Kili at this time, and for this reason the March-to-May season is known as the long rains. This is the main wet season on Kilimanjaro. As the south-east trade winds run into the southern side of Kili, so the southern slopes tend to be damper and as a consequence more fertile, with the forest zone much broader than on the northern slopes.
Then there are the dry ‘anti-trade’ winds from the north-east which carry no rain and hit Kilimanjaro between May and October. These anti-trade winds, which blow, usually very strongly, across the Saddle (the broad valley between Kilimanjaro’s two peaks), also serve to keep the south-east trade winds off the upper reaches of Kilimanjaro, ensuring that the rain from the long monsoon season stays largely on the southern side below 3000m, with little falling above this. This is why, at this time of year, the first day’s walk for trekkers following the Marangu, Umbwe or Machame routes is usually conducted under a canopy of cloud, while from the second day onwards they traditionally enjoy unadulterated sunshine
A second seasonal rain-bearing wind, the north-east monsoon, having already lost much of its moisture after travelling overland for a longer period, brings a short rainy season between November and February. While the northern side receives most of the rain to fall in this season, it is far less than the rain brought by the south-east trade winds, and as a result the northern side of the mountain is far drier and more barren in appearance. Once again, the rain falls mainly below 3000m.
So how did Kilimanjaro’s glaciers get there?
This model of Kilimanjaro weather does pose a tricky question: if the precipitation falls below 3000m, how did the snows on the summit of Kibo get there in the first place? The answer, my friend, is blowing in the (anti-trade) wind: though these winds normally blow very strongly, as those who walk north across the Saddle will testify, they occasionally drop in force, allowing the south-east trade winds that run beneath them to climb up the southern slopes to the Saddle and on to the summit. Huge banks of clouds then develop and snow falls. This, at least, is the theory of Kilimanjaro’s climate. In practice, of course, the mountain is rarely so predictable.
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