The weather in Lapland can turn one hundred and eighty degrees in the course of twenty minutes. A sunny morning, good visibility to the horizon, a barely perceptible wind — and three hours later you are sitting in the tent and waiting for the front to pass. To cope in these conditions you do not need to be a meteorologist or to know the names of all the cloud species. It is enough to know what to look at and what to do with what you see.
The morning ritual — before you leave camp
Before in the morning I pack the last things and set off, I spend a few minutes looking carefully at the sky and the wind. I compare the direction of the wind with the one it had in the evening — if it has changed, that is a signal that something is coming. If I have with me a watch with a barometer, I check the pressure, and I am particularly interested in a sudden drop during the night, because that is the classic announcement of a front. A sunny morning with thin feathery clouds high in the sky obliges me to glance upward every two hours and check whether the cirrus is not beginning to thicken — this thickening veil is often a warning sent twelve to eighteen hours before the change.
Clouds — your free barometer
Cumulus are those white, puffy clouds with a flat base, which in fair weather look decorative and announce nothing bad. They become dangerous only when they begin to grow vertically and darken — that is when we are dealing with cumulonimbus, meaning storms, strong wind and violent precipitation. If you see that the clouds are growing upward faster than they are moving across the sky, you have at most an hour, two in reserve before things begin to happen.
Cirrus, meaning those thin, feathery streaks high in the sky, usually announces a warm front within a day or two. When the cirrus gradually thickens and turns into altostratus — a uniform, grey veil covering the sun — the front is already considerably closer than it might seem.
Wind — read the direction, not only the strength
In Scandinavia a wind from the west usually brings moisture from over the Atlantic, a wind from the north cold and clearings, and a wind from the south a warming often combined with precipitation. These are of course not absolute rules, rather patterns that in most cases hold and which are worth keeping in mind.
You also have to remember that the wind on the ridge is a completely different story from the wind in the valley or over a river at a crossing. When you are still standing in the silence of the valley, and on the pass you hear a deep roar, it is better not to assume that things will stay the same on the other side of the climb. Very often the weather in one valley is completely different from the next.
When to turn back — decision thresholds
- Visibility drops below one hundred metres, and the terrain is not well known to you
- The wind makes it hard to stand in place and to keep balance
- A storm appears exactly on the line of your march
- The temperature drops sharply and it turns out you do not have the appropriate layers
After turning back — what to do next
Turning back from the route is not the end of the day, only a decision that saves the day. The first thing I do then is mark on the map the point from which I turned back, and the hour — because one usually returns by the same way, and visibility does not always allow it. I look for a sheltered place for a bivouac, most often in the valley or under the ridge on the leeward side. If I have a satellite communicator, I will update the position. Then I stay in place until the weather clears — I do not set off into fog with the thought that „maybe it will improve”. The signal to continue must be a real improvement in visibility, and not my own optimism.
The forecast and reality
Before every trip I check the forecast on yr.no, the Norwegian meteorological service, which in Scandinavia works better than most commercial applications. One has to remember, however, that a forecast is always only a forecast, and in the Arctic mountains the numerical models can be very wrong with local phenomena. That is why I always assume a scenario somewhat worse than the one declared and pack with the thought that the conditions will change. Layers of clothing, a foil blanket and the knowledge of when to stop are in the end more effective than the most accurate forecast.
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