Alpine climate

Alpine climate is the kind of weather you find high up in the mountains, where it gets very cold and trees cannot grow. This happens because the air is thin and the temperature drops a lot as you go higher. Such places are often called mountain climates or highland climates.

At these heights, the weather can change quickly. It might be very cold, with snow covering the ground much of the year. Even during what we call summer, nights can still be freezing. This special climate affects the kinds of plants and animals that can live there, creating unique and beautiful landscapes.

People who visit or live in these areas need to be prepared for sudden weather changes and harsh conditions. Understanding alpine climate helps us protect these special mountain environments and plan safe adventures in high places.

Definition

There are many ways to describe an alpine climate. In the Köppen climate classification, alpine and mountain climates are grouped with the polar climate, where no month gets warmer than 10 °C (50 °F).

According to the Holdridge life zone system, two main mountain climates stop trees from growing. One is the alpine climate, which happens when the average temperature, after adjusting for very cold and very hot days, stays between 1.5 and 3 °C (34.7 and 37.4 °F). This is similar to the warmest tundra climates in the Köppen system. The other is the alvar climate, the coldest mountain climate, where this adjusted temperature is between 0 °C and 1.5 °C. It matches the coldest tundra climates and ice cap climates.

The way the alpine climate changes through the year depends on where you are. In places near the equator, like the top of Mauna Loa, temperatures stay about the same all year. In places farther from the equator, like Mount Washington in New Hampshire, temperatures change with the seasons but never get very warm.

Cause

The temperature in the air depends on how sunlight heats the ground and how warm air moves upward. When the ground gets hot from the sun, it warms the air right above it. Hot air rises because it is lighter than cooler air, carrying heat higher into the sky. As the air goes higher, it gets colder and thinner.

When air rises and cools, the water vapor in it can turn into clouds. This releases some heat, which changes how fast the temperature drops as you go higher. Usually, the temperature drops about 5.5 °C for every 1,000 meters you climb a mountain. Going up in the mountains feels a bit like moving toward the north pole in terms of how cold it gets. The higher you go, the more likely it is to snow, and the wind also gets stronger. The temperature stops dropping when you reach about 11,000 meters, though this is higher than any mountain top.

radiation convection visible spectrum greenhouse effect adiabatic process heat of vaporization saturated clouds dry adiabatic lapse rate moist adiabatic lapse rate environmental lapse rate latitude oceans precipitation snow winds tropopause summit

Distribution

Alpine climates are found in many mountainous areas around the world. Some places with this type of climate include:

• Asia
  • Himalayas
  • Tibetan Plateau
  • Gansu
  • Caucasus Mountains
  • Qinghai
  • Mount Lebanon
• Europe
  • Alps
  • Urals
  • Pyrenees
  • Scandinavian Mountains
  • Scottish Highlands
• South America
  • Andes
• North America
  • Sierra Nevada in California
  • Cascade Range
  • Rocky Mountains
  • Torngat Mountains, Canada
  • Trans-Mexican Volcanic Belt
• Africa
  • Atlas Mountains
  • Ethiopian Highlands
• Oceania
  • Southern Alps of New Zealand
  • Tasmania
  • Mount Pico in the Atlantic
  • Mauna Loa in the Pacific

The height at which alpine climate begins changes depending on where you are in the world. In very northern places like Sweden, it can start as low as 650 metres (2,130 feet). But on tall mountains like Mount Kilimanjaro in Tanzania, it begins much higher, around 3,950 metres (12,960 feet).