The sea of fog over Salzburg

The fog over Salzburg has a bad reputation, and it has earned every bit of it. Spend a week beneath it in November and you switch the lights on at noon without giving it a second thought. All the stranger, then, to see it from above for the first time, on one of those days, from the Gaisberg. What was a grey lid over the city is, up here, a white and perfectly motionless plain that reaches to the foot of the Untersberg and looks firm enough to walk across.

It takes very little: a few clear nights in which the cold flows down the slopes into the valleys and stays there, because warmer air lies above it. The fog forms where the two meet, and the low November sun no longer has the strength to burn it off. So it stays, sometimes for days. A few hundred metres higher, it is still October.

The city notices none of this. It sits under a lid, and whatever wants to rise does not get far. On such days the smoke from the chimneys hangs in the lanes of the old town and does not clear.

Up here it is a different day. The sun has been warming the slope since mid-morning, the grass is dry, and from the trees at the edge of the forest comes a scent one would no longer expect at this time of year. It smells of October. Standing here in shirtsleeves, you look down on a city you cannot see and know that it is pulling its scarves a little tighter.

Across the way, the Untersberg rises out of the white, the mountain Salzburg has been telling stories about for centuries. Inside it, they say, an emperor sits asleep at a marble table, and every hundred years he sends someone to see whether ravens are still circling the summit. As long as they circle, he sleeps on.

When the fog takes on colour

The finest hour comes at the end. The light turns golden, the peaks cast long blue shadows across the fog, and for a few minutes it turns pink before it fades to grey. Whoever meant to set off already stops once more and looks.

On the way down, the edge of the fog can be read from the trees to the metre. There they are often covered in hoarfrost, white twig by twig, while a few steps higher everything is dry. Then the air turns damp, and the jacket you did not want to put on up top is now too thin.

Down below, it is November again. It still smells of chimney smoke. But now you know that the fog has a top side.

ARVE Chaleureux · The last hour of sun

Frequently asked questions

How does a sea of fog form? During a temperature inversion. On long, clear nights cold air collects in valleys and basins, with warmer air above it. Low cloud forms at the boundary, and from above it looks like a sea.

What is an inversion? A reversal of the usual temperature layering: instead of getting colder with height, it is warmer above than below.

When can you see a sea of fog? Mainly in late autumn and winter, in high-pressure weather. It lies calmest in the early morning and takes on colour shortly before sunset.

Why is it sometimes warmer on the mountain than in the valley? Because the cold, heavy air collects below while the sun shines above and warmer air lies on top. The weak autumn sun often cannot clear the fog beneath.

What legend is told about the Untersberg? That an emperor sleeps inside it, his beard growing around a marble table. Every hundred years he sends someone to see whether ravens are still circling the summit. As long as they circle, he sleeps on. Depending on the version, it is Charlemagne or Frederick Barbarossa.