Weather in the mountains: what to know about fog, wind and lightning

A city forecast does not work for the mountains. An app showing "clear, 28 °C" for Baku knows nothing about what is happening on the Shahdag ridge.

Three simple rules

1. Temperature drops by roughly 0.6 °C every 100 metres of altitude. At 2000 metres it is 12 degrees colder than in the city — and then wind is added on top.

2. Mountain weather worsens after midday. Air rising from slopes warmed in the morning creates midday cloud and sometimes rain. That is exactly why routes start early.

3. Wind "lowers" the temperature. At 5 °C, a 40 km/h wind feels below zero to the body. A windproof outer layer matters more than a warm one.

Fog

In the mountains fog descends in 10–15 minutes and visibility drops to 20 metres.

What to do:

• Stop immediately and gather the group together
• Move at a distance where you can see one another
• Do not leave the trail — a "shortcut" is the most dangerous decision in fog
• If the fog does not lift, turning back is the right call

Lightning

On a summit or an open plateau, lightning is a serious danger.

The most dangerous places: summits, ridge lines, a lone tree, metal structures, the water's edge.

What to do:

• Descend from the summit immediately
• Spread the group out — several metres apart
• Crouch with your feet together; do not lie flat on the ground
• Keep trekking poles and metal objects away from you

Estimating distance: divide the seconds between the flash and the thunder by 3 — the result is roughly the distance in kilometres. Less than 15 seconds means the storm is very close.

Making the decision

The hardest decision is turning back. But there is a rule for it: the turnaround time is set in advance. For example, "if we are not on the summit by 13:00, we turn back". Making that call while tired and close to the top is hard, which is why it is made beforehand.

The mountain stays where it is. It sounds like a cliché, but it is the thought that saves the most lives in the mountains.

When choosing a route: difficulty grades. For clothing: the layering principle.