Location, Formation and Climate of a Glaciated Landscape

The Lake District: why its location matters

The Lake District in Cumbria, north-west England, is a distinctive glaciated upland landscape. Its mountains, steep-sided valleys and long lakes reflect the interaction of geology, past ice and continuing physical and human processes.

Its location matters in two connected ways. It lies close to the sea, exposed to moist air arriving from the Atlantic on prevailing westerly winds. It also contains high mountains that force this air upwards, producing heavy rainfall. Meanwhile, the sea moderates temperatures because it warms and cools more slowly than the land. Atlantic ocean circulation also helps give the area milder winters than might otherwise be expected at its latitude of about 54–55° north.

Height creates important local differences. Mountain tops are colder and more exposed than valley floors, so the Lake District does not have one uniform climate. These differences affect snow, erosion, farming and the conditions experienced by visitors.

The rock foundation came before the glaciers

The central Lake District provides an igneous-rock example of a glaciated upland. The Borrowdale Volcanic Group consists of hard lavas and volcanic ashes formed during eruptions about 450 million years ago. These rocks make up high, craggy mountains including Scafell, Helvellyn and the Langdale Pikes.

These mountains are not the surviving shapes of the original volcanoes. They are resistant volcanic rocks that have remained while surrounding material has been eroded. Folding and uplift helped create the mountainous landscape before glaciers reshaped it.

Other rocks help explain contrasts within the area. The older Skiddaw Group in the north originated as seabed muds and sands and was later raised and deformed. The Windermere Group includes sedimentary rocks that contribute to the gentler scenery of southern Lakeland. Geology therefore supplied both the starting landscape and differences in resistance to erosion.

Ice reshaped the mountains and valleys

During repeated ice ages over the last two million years, glaciers covered the Lake District. The area was covered in ice more than 20,000 years ago. Glaciers flowed outwards from the central mountains, following and enlarging existing river valleys.

Moving ice eroded the valleys. Rock fragments carried at the glacier's base scraped the bedrock through abrasion, while plucking removed pieces of rock. Together these processes widened and deepened valleys, producing broad floors and steep sides: the characteristic U-shaped cross-section.

Langdale is a named example of a U-shaped valley. Glacial erosion also created deep basins that filled with water after the ice melted, producing ribbon lakes such as Windermere. The valleys and long, narrow lakes radiate outwards from the central uplands, rather like spokes from the hub of a wheel.

Glaciers also transported material and deposited it as they melted or retreated. Easedale Valley contains ground and recessional moraines: deposits left beneath ice and at positions where a retreating glacier's margin paused. Ennerdale contains erratics, rocks transported by ice away from their place of origin. These depositional features show that glaciers did more than carve the landscape.

Why the Lake District is so wet

Prevailing westerly winds carry moisture from the Atlantic. When this air reaches the mountains, it is forced to rise. Rising air cools, water vapour condenses into cloud droplets, and rainfall follows. This is relief rainfall, also called orographic rainfall.

The resulting wet climate supplies the lakes and rivers and contributes to continuing erosion. However, rainfall varies considerably between places, so a figure from one valley should not be treated as the rainfall total for the whole Lake District.

Using climate data to explain the landscape

These figures describe different aspects of the Lake District's climate:

Start by identifying what each number measures. Keswick's figures are monthly averages of daily temperature, not the temperatures on two particular days. Subtracting 4.7°C from 15°C gives a 10.3°C difference between the December and July averages. This shows seasonal variation, but it is not a measure of the most extreme temperatures experienced there.

Seathwaite's annual rainfall total demonstrates how wet a particular upland valley can be. It is consistent with moist Atlantic air being lifted over the mountains. Heavy rainfall supplies rivers and can help them transport sediment and erode their channels.

The snowfall comparison shows the importance of altitude. Helvellyn can have up to 47 more days with snowfall than the approximate valley figure. Higher land is colder, so snow is more likely there. Days on which snow falls are not the same as days on which snow remains on the ground.

These are climate summaries, not forecasts. They help explain typical conditions, but they cannot tell a walker whether a particular afternoon will be safe. Nor do averages alone demonstrate a trend in climate change: that requires comparable records over time.

Which factors matter most in landscape change?

Geology and past glaciation are the most significant factors in the landscape's overall form. Resistant rocks helped preserve high mountains, while glaciers created the large valleys and lake basins. These changes operated over very long periods and across large areas.

Today, rivers and weathering continue to modify this inherited landscape. The wet climate supplies flowing water, while freezing conditions on higher ground contribute to the breakdown of exposed rock. Present-day processes alter the details rather than creating a new glacial landscape.

Human activity can produce more rapid, concentrated changes. Tourism contributes to soil erosion on heavily used routes and changes the landscape through facilities. Water supply has also altered glacial valleys: Thirlmere and Haweswater are reservoirs, and the flooding of Mardale Valley to create Haweswater changed its landscape and ecosystem.

The factors interact. Wet weather can make disturbed ground more vulnerable to erosion, while steep, rocky terrain and cool conditions favour hill sheep farming over arable farming. A strong judgement therefore depends on the question: ice and geology explain the major landforms, whereas human intervention can be especially significant for recent change at particular sites.