In Vestland the fjord is thirteen hundred metres deep and a hundred at its mouth
The Sognefjord runs 205 kilometres inland and drops to 1,308 metres deep, but near its mouth the floor rises abruptly to about 100. No sea digs like that. Ice does, and only while it stays hemmed in.
A fjord looks like an arm of the sea, and it is one: salt water pushed in between mountains. But the sea did not make it. The sea only arrived at the end, when the work was already done.
What gives it away is the profile of the floor. A valley cut by running water falls continuously towards its mouth; this one climbs just before it gets out. Only a tongue of ice does that.
01 Two hundred and five kilometres inland
The figures are hard to take in. The main fjord runs 205 kilometres from the ocean to the head of its last arm, and reaches 1,308 metres deep in its central section. For about a hundred kilometres at a stretch it is over a thousand metres.
And all of that in very little width: six kilometres at most, averaging under five. That is, a trench more than a kilometre deep and five wide running across half the region.
The territory it is cut into covers 33,871 square kilometres and holds 638,821 people, some twenty per square kilometre. Most live on the coast or on valley floors, because the rest is, quite simply, on edge.
02 The step at the mouth
Here is the odd part. Near the mouth, the fjord floor rises abruptly to about 100 metres below the surface. Geology calls that a sill, and it means the shallowest point of the whole run is right at the exit.
Even those 1,308 metres are not the full figure. The bed is covered by some 200 metres of sediment laid down afterwards, so the rock actually excavated lies about 1,500 metres below sea level.
Think about it for a moment: there are over fourteen hundred metres of difference between the fjord's floor and the step separating it from the ocean. The water inside is, to a large extent, impounded behind that sill.
03 Why ice digs like that
A glacier does not behave like a river. It erodes in proportion to pressure and to the speed at which it moves, and both depend on how confined it is. While the ice grinds down squeezed between two walls, it works like a gouge.
That is why it can excavate below sea level without any trouble: it does not need a gradient to take water somewhere, it only needs mass pushing from above. Hence the thousand-odd metres below the sea in the central section.
And that is why, when it reaches the coast and the valley opens out among islands and low ground, the tongue spreads, loses thickness and loses its power to cut. The sill appears exactly where the ice stopped being hemmed in. The step at the mouth is not an obstacle: it is the mark of where the work ended.
04 The tool still exists
The best thing about this region is that you do not have to imagine anything. Continental Europe's largest glacier is still there, inland, with 487 square kilometres of surface, over sixty kilometres of length and up to six hundred metres of thickness.
From its central mass, tongues come down to three hundred metres above sea level, almost to the height of the inhabited valleys. You can stand at the edge of one and watch the mechanism working: the polished rock, the crevasses, the river of cloudy water coming out underneath.
And there is a detail that explains everything. That glacier is sustained not by cold but by snow: so much falls in winter that it offsets a very intense summer melt. Which is to say, what keeps the ice there is the same Atlantic moisture that soaks the coast the rest of the year.
05 Where people fit
A trench with vertical walls leaves very little horizontal ground, and everything concentrates there. Villages appear where a side valley meets the fjord and has left a shelf of material, or where the slope lies back just enough to allow some meadow.
Those shelves are tiny compared with the mountain behind them, but they are extraordinarily productive. On one of the southern branches, the Hardanger district produces around forty per cent of the country's fruit: apples, plums, pears and cherries at sixty degrees of latitude.
The reason is that same body of water. A deep fjord does not freeze and it stores heat, so the strip along the shore has a far milder climate than its latitude would grant it. The orchard is where it is because there is a kilometre of water underneath.
06 How to travel it
The first rule is to count time in crossings, not kilometres. The road hugs the shore, climbs to a pass, drops again and takes enormous detours around every arm, so two points in sight of each other can be two hours apart by car and twenty minutes by boat.
The second is to use the water as a road, because that is what it has always been. The ferry and the fast boat are not an added tourist attraction: they are the transport system that makes living in a place like this possible, and from them you see the real scale of the walls.
And the third is a way of looking. When you cross the fjord's mouth, among low islands and open sea, remember that you are passing over the shallowest point of the whole run. Behind you, inland, the floor drops a kilometre and more. That is the exact spot where the ice gave up.
