The Great Frosts

Cold at the Summit

Hampstead has always been a place apart from the rest of London, and never more so than in winter. Perched on its hill at 440 feet above sea level — the highest point in the metropolitan area — the village experiences weather that can be markedly different from the streets below. When rain falls on Holborn and the Strand, it sometimes falls as sleet on Hampstead Heath. When the Thames-side parks are damp and grey, the hilltop can be wrapped in freezing fog or dusted with snow that vanishes before it reaches the Finchley Road. This elevation, combined with the exposed position of the Heath and the particular characteristics of the Bagshot Sands geology beneath it, has given Hampstead a long and vivid relationship with extreme cold — a relationship that stretches back through centuries of recorded history and that has shaped the physical landscape, the social customs, and the collective memory of the area in ways that are still visible today.

The great frosts of history — those prolonged periods of extreme cold that froze rivers, killed livestock, halted trade, and transformed the familiar landscape into something strange and beautiful — hit Hampstead harder than almost anywhere else in London. The village's elevation meant that temperatures on the hilltop could be several degrees lower than in the sheltered valleys below, and the shallow ponds that dotted the Heath froze more quickly and more deeply than larger bodies of water at lower altitudes. When the rest of London shivered, Hampstead was often buried in snow and ice, its lanes impassable, its wells frozen, its inhabitants huddled around fires in their timber-framed cottages while the wind howled across the open Heath.

But extreme cold was not merely a hardship to be endured. It was also an opportunity — for commerce, for recreation, and for the kind of communal spectacle that binds a neighbourhood together. The frozen ponds of Hampstead became skating rinks, gathering places, and — most importantly — sources of ice that could be harvested, stored, and sold throughout the warmer months. The history of Hampstead's great frosts is a history of suffering and celebration, of danger and delight, of a community shaped by its climate in ways both practical and poetic.

The Great Frost of 1683-84

The most severe winter in recorded English history began in late December 1683 and continued without significant respite until February 1684. It was a cold of a kind that modern Londoners can barely imagine. The Thames froze solid from bank to bank — not merely a skin of ice at the margins, but a sheet thick enough to bear the weight of coaches, cattle, and the enormous temporary structures of the Frost Fair that sprang up on the river's surface. From London Bridge to Temple, the frozen Thames became a street of booths, stalls, and taverns, with printing presses, puppet shows, and ox-roasting pits arranged along avenues marked out on the ice. It was the greatest and most famous of all the Thames frost fairs, and it lasted for nearly two months.

If the Thames was frozen solid at sea level, the conditions on Hampstead Hill must have been extraordinary. Although direct records from the village during this period are sparse — Hampstead was still a small rural settlement, and its literate inhabitants were few — the general accounts of the Great Frost describe conditions that would have been even more extreme at higher elevations. Temperatures across southern England fell to minus twenty degrees Celsius or lower. The ground froze to a depth of several feet. Trees split open from the cold, their sap expanding as it froze and bursting the bark with reports that sounded like pistol shots. Birds fell dead from the sky, and livestock perished in the fields.

On the Heath, the ponds would have frozen within days of the cold setting in, and the ice would have continued to thicken throughout the two months of frost. The Highgate and Hampstead ponds — which were at this period used as reservoirs to supply water to the growing city below — became solid blocks of ice, cutting off the water supply and creating serious difficulties for the communities that depended on them. The springs that emerged from the Bagshot Sands — the sources of the chalybeate waters that would later make Hampstead famous as a spa — would have slowed to a trickle or frozen altogether, their mineral-rich waters forming strange columns and cascades of ice on the hillside.

The Great Frost of 1683-84 was caused by a combination of meteorological factors that aligned with devastating effect. A persistent high-pressure system over Scandinavia drew bitterly cold air from the Arctic across the North Sea and into southern England. The absence of significant wind meant that the cold air settled in the valleys and lowlands, creating temperature inversions that trapped the coldest air at the surface. And the winter of 1683-84 fell within the period that climatologists call the Little Ice Age — a prolonged cooling of the Northern Hemisphere that lasted from the fourteenth to the nineteenth century and that produced some of the coldest winters in European history.

The Frost of 1739-40

If the Great Frost of 1683-84 was the most famous winter in English history, the frost of 1739-40 was in many respects even more severe and certainly more prolonged in its effects. The cold began in late October 1739 — extraordinarily early, even by the standards of the Little Ice Age — and continued with only brief interruptions until late March 1740. This five-month winter was one of the longest and most brutal in European history, and it caused widespread suffering across the continent. In Ireland, it became known as the "Great Frost" and led to a famine that killed tens of thousands. In England, the poor suffered terribly, with fuel prices soaring and food supplies disrupted by the impassable roads and frozen rivers.

By 1739, Hampstead was beginning to develop into something more than a rural village. The discovery of the chalybeate springs earlier in the century had attracted visitors seeking to take the waters, and a small but growing community of wealthy residents had begun to build houses along the High Street and on the slopes below the Heath. These residents would have experienced the frost of 1739-40 with particular intensity. The elevation of the village, which was prized in summer for its clean air and views, became a liability in winter, exposing the hilltop to the full force of the cold winds that swept in from the north and east.

Contemporary accounts from London describe scenes of extraordinary hardship. The Thames froze once again, though not as solidly as in 1684, and the streets were blocked by snow and ice for weeks at a time. Coal deliveries — the lifeblood of domestic heating — were disrupted by the freezing of the rivers and canals that carried fuel from the mines of the north. Prices for food and fuel rose to levels that placed them beyond the reach of the labouring poor, and charitable subscriptions were raised to provide relief. In Hampstead, the effect would have been compounded by the difficulty of the steep hill that connected the village to the flatlands below. Carts laden with supplies would have found it impossible to climb the icy gradient of Heath Street, and the village would have been effectively cut off from the markets and warehouses of central London for days at a time.

The ponds of the Heath froze deeply during this winter, and the ice would have been thick enough for harvesting — a practice that, by the mid-eighteenth century, was becoming increasingly important to the London economy. Ice harvested from ponds and lakes in the winter months was stored in purpose-built ice houses — deep, insulated chambers dug into the earth — and used throughout the summer to preserve food, cool drinks, and make the iced desserts that were becoming fashionable among the wealthy. The Hampstead ponds, with their elevation and exposure, produced ice of particularly good quality — clear, hard, and slow to melt — and the great frosts of the eighteenth century would have been bonanza years for the ice merchants who worked the Heath.

Ice Harvesting from the Hampstead Ponds

The business of ice harvesting was, for several centuries, an important economic activity on Hampstead Heath, and it illustrates the way in which extreme cold could be turned from a hardship into a commodity. The ponds of the Heath — particularly the chain of ponds that runs through the valley between Hampstead and Highgate — were ideally suited to ice production. Their elevation meant they froze earlier and more deeply than lowland ponds; their relatively small size meant the ice could be harvested efficiently; and their proximity to the wealthy households of London meant the harvested ice could be transported to market without excessive cost or wastage.

Ice harvesting was hard, dangerous work. The ice men — often casual labourers hired for the purpose — would wait until the ice on the ponds had reached a thickness of several inches, then mark out the surface into rectangular blocks using long-handled saws and scoring tools. The blocks were cut free, levered out of the water with iron hooks, and loaded onto carts for transport to the ice houses where they would be stored. The work had to be done quickly, before the exposed water refroze and before the ice became too thin at the edges to support the workers' weight. Accidents were common: men fell through the ice, were struck by swinging blocks, or suffered frostbite and exposure during the long hours of work in sub-zero temperatures.

The ice houses of Hampstead were scattered across the Heath and the surrounding estates. These were substantial structures — typically a deep pit, lined with brick and insulated with straw, with a domed or arched roof and a small entrance at the top. The harvested ice was packed into the pit in layers, separated by straw, and the entrance was sealed to keep out the warm air. A well-built and well-maintained ice house could keep ice frozen throughout the summer, even during hot weather, and the ice could be sold to fishmongers, caterers, confectioners, and private households at prices that rose steeply as the summer advanced and the stored supply diminished. The remains of several ice houses can still be found in the grounds of the larger houses around the Heath, though most are now filled in or converted to other uses.

The ice trade reached its peak in the late eighteenth and early nineteenth centuries, before the development of mechanical refrigeration made it obsolete. During this period, the great frosts were eagerly anticipated by the ice merchants, who stood to make substantial profits from a hard winter. The frost of 1813-14, for example — a winter that saw the last great frost fair on the Thames — would have been a particularly productive season for the Hampstead ice harvesters. The ice on the ponds would have been exceptionally thick and clear, and the demand for stored ice in the following summer would have been high, as the return of warmer weather always brought with it a surge in orders from the hotels, clubs, and great houses of central London.

The Winter of 1947

The most severe winter in modern British history arrived without warning in late January 1947 and lasted until mid-March, bringing the country to a standstill at a moment when it was least able to cope. Britain in 1947 was still recovering from the Second World War. Food rationing was still in force, coal supplies were depleted, and the national infrastructure was in a state of exhaustion after six years of conflict. The winter struck this weakened nation with extraordinary force. From 23 January, when the first snowfall blanketed southern England, until mid-March, when the thaw finally came, the country was gripped by a cold that was relentless, punishing, and seemingly unending.

Hampstead experienced the 1947 winter with particular severity. The Heath was buried under deep snow that drifted in the hollows and on the sheltered slopes, in some places reaching depths of several feet. The ponds froze solid, and the ice became thick enough for skating — a recreation that had been largely impossible during the relatively mild winters of the preceding decades. Photographs from the period show bundled-up Londoners skating on the Highgate Ponds, playing ice hockey on the Mixed Bathing Pond, and even sliding down the slopes of Parliament Hill on improvised toboggans made from tea trays and dustbin lids.

But behind the scenes of winter recreation, the 1947 frost caused serious hardship. The coal shortage, already acute before the winter began, became a crisis as demand for heating fuel soared. Electricity was rationed, with power cuts affecting homes and businesses for hours at a time. Factories were forced to close, putting thousands of workers on short time. Food supplies, already constrained by rationing, were further disrupted by the freezing of roads and railways. On Hampstead Hill, the steep gradients became treacherous, and several residents recall the difficulty of simply reaching the shops on Heath Street or the Underground station at Hampstead, where the tunnels and platforms offered a welcome respite from the bitter cold above ground.

The thaw, when it finally came in mid-March, brought its own dangers. The enormous accumulation of snow and ice on the Heath and the surrounding hills melted rapidly, sending torrents of water cascading down the slopes and into the streets below. The ponds, which had been frozen for nearly two months, overflowed their banks as the ice melted and the meltwater poured in from the surrounding catchment. Flooding affected several of the lower-lying streets around the Heath, and the drainage systems — many of them dating from the Victorian era — were overwhelmed by the volume of water. The 1947 thaw was a reminder that extreme cold, however dramatic and picturesque, always ends with a deluge — and that the infrastructure of a city built on hills must be designed to cope with the consequences.

Climate, Elevation, and the Hampstead Microclimate

The relationship between Hampstead's elevation and its climate is more complex than a simple equation of height equals cold. While it is true that temperatures generally decrease with altitude — at a rate of roughly one degree Celsius per 150 metres of elevation in the British climate — the actual weather experienced on Hampstead Hill is shaped by a range of factors that interact in subtle and sometimes unpredictable ways. The result is a microclimate that can differ significantly from the conditions experienced at lower altitudes, not always in the direction that simple theory would predict.

The most important factor is exposure. Hampstead's hilltop position means it is open to winds from all directions, and particularly to the cold easterly and north-easterly winds that bring the most severe winter weather to south-east England. These winds, which originate over the frozen plains of Scandinavia and northern Europe, lose little of their force as they cross the flat terrain of East Anglia and the Thames estuary, and they strike the exposed summit of Hampstead Hill with undiminished ferocity. The effect is to lower the wind-chill temperature significantly below the actual air temperature, making Hampstead feel colder than its elevation alone would suggest.

Conversely, the Heath's position on the Bagshot Sands — a free-draining sandy soil that loses moisture rapidly — means that the hilltop dries out quickly after rain, reducing the risk of the ground-frost that can persist for days on the heavier clay soils at lower altitudes. This paradox — that Hampstead can be windier and colder in the air while drier and less frost-prone at ground level — creates conditions that are peculiarly favourable to certain types of vegetation, particularly the heathland species that give the Heath its name.

The urban heat island effect adds another layer of complexity. Central London, with its dense concentration of buildings, vehicles, and human activity, generates a significant amount of waste heat that raises the ambient temperature by several degrees above the surrounding countryside. This effect diminishes with distance from the centre, and Hampstead, on the northern fringe of the metropolitan area, experiences a weaker heat island effect than central locations. In practical terms, this means that Hampstead sits in a transitional zone between the warmth of the city and the cooler temperatures of the open countryside beyond — a zone where the balance between urban heat and rural cold is delicately poised and where small changes in wind direction or cloud cover can tip the balance one way or the other.

The implications for winter weather are significant. During prolonged cold spells, when the urban heat island is at its strongest and central London temperatures may hover just above freezing, Hampstead can be several degrees colder, with temperatures dropping below zero and staying there for days at a time. This differential is particularly marked during calm, clear nights, when the absence of wind allows cold air to drain off the hilltop and collect in the valleys below, creating frost hollows where temperatures can fall dramatically. The Vale of Health, a low-lying area in the heart of the Heath, is particularly prone to this effect, and on clear winter nights it can be significantly colder than the hilltop above it — a counter-intuitive reversal that catches many residents by surprise.

Frost, Memory, and the Character of Place

The great frosts have left their mark on Hampstead in ways that go beyond the physical landscape. They have shaped the collective memory of the place, contributing to a sense of Hampstead as somewhere slightly wild, slightly exposed, slightly apart from the comfortable warmth of the city below. The stories of frozen ponds, snowed-in villages, and ice harvesting on the Heath are part of the oral history of the neighbourhood, passed down through generations and retold with the mixture of horror and nostalgia that extreme weather always inspires.

The architecture of the area bears witness to the challenge of cold winters at elevation. The substantial brick walls, deep-set windows, and massive chimney stacks of the older Hampstead houses were not merely decorative — they were practical responses to a climate that could be harsh and unforgiving. The thick walls provided insulation; the small windows minimised heat loss; the generous fireplaces, often equipped with complex flue systems that heated multiple rooms, were the heart of the household's defence against the cold. Even the orientation of the houses, with their principal rooms facing south to catch the winter sun, reflects an awareness of the climatic challenges of the hilltop location.

The ponds themselves carry the memory of the great frosts in their very existence. Several of the ponds on the Heath were originally created or enlarged to serve as reservoirs for the water supply to central London, and their management has always taken account of the risk of prolonged freezing. The depth and profile of the ponds, the arrangement of their overflow channels, and the construction of their dams all reflect centuries of experience with extreme cold and its aftermath. The chain of ponds is, in this sense, a piece of climate engineering — a system designed to manage water in a landscape where the transition from frost to thaw can be sudden and dramatic.

Today, the great frosts are becoming rarer. The combination of global warming and the strengthening urban heat island means that the kind of prolonged, severe cold that once froze the Thames and turned the Hampstead ponds into skating rinks is now an exceptional event rather than a regular occurrence. The last winter that approached the severity of 1947 was 1962-63, when heavy snowfalls and prolonged frost again disrupted life across southern England. Since then, winters have been generally milder, and the ponds of the Heath have frozen over only occasionally and briefly. The ice houses have fallen into disuse; the ice merchants have disappeared; and the memory of the great frosts is fading from living recollection.

Yet the possibility of extreme cold has not been eliminated, and the history of the great frosts serves as a reminder that the climate is not as stable or as predictable as we sometimes assume. The factors that produced the great frosts of the past — the vagaries of atmospheric circulation, the influence of solar activity, the complex interplay of ocean currents and ice sheets — are still at work, and their effects, while modulated by the warming trend of recent decades, have not been abolished. Hampstead, on its exposed hilltop, with its ancient ponds and its memories of ice and snow, remains a place where the elemental forces of weather and climate are felt more keenly than in the sheltered streets below — a reminder that London is not merely a city but a landscape, subject to the same natural forces that have shaped it for millennia.

*Published in the Hampstead Renovations Heritage Collection — exploring the architecture, history, and stories of London's most remarkable neighbourhoods.*