UK Weather Hazards and Extreme Events

How weather becomes a hazard

Weather describes short-term atmospheric conditions; climate describes their long-term pattern. Extreme weather is unusually severe for a particular place and time of year. It becomes hazardous when it threatens people, property, livelihoods or ecosystems.

The UK lies in the path of Atlantic weather systems, so changing conditions and storms are a normal part of its climate. However, the consequences depend on both the weather and the places affected. Heavy rain falling onto already saturated ground can cause much more flooding than the same rainfall after a dry period.

The range of UK weather hazards

Heavy rain and flooding can inundate homes, close roads and damage crops. Rivers may overflow when water enters them faster than it can be carried away. Intense rainfall can also cause surface-water flooding when drains and the ground cannot absorb it quickly enough.

Strong winds can bring down trees and electricity lines, damage buildings and disrupt transport. Coastal storms can also drive seawater onto low-lying land, especially when they coincide with high tides.

Snow, ice and severe cold make travel dangerous and can interrupt work, education and deliveries. Cold conditions also threaten health, particularly among vulnerable people.

Heatwaves increase the risk of heat-related illness and place pressure on water supplies. Droughts develop during prolonged periods of unusually low rainfall, reducing the water available for households, farming and ecosystems. Heatwaves and droughts can occur together, but they are different hazards: one concerns temperature, the other a shortage of rainfall.

Several hazards can occur during the same event. A storm may bring heavy rain, flooding and damaging winds, making the response more difficult.

Storm Babet: a recent UK example

Storm Babet affected the UK from 18–21 October 2023. It was an extratropical cyclone: a low-pressure storm developing outside the tropics, rather than a tropical cyclone. Particularly severe impacts occurred in eastern Scotland and parts of northern England.

In Brechin, Angus, the River South Esk overtopped flood defences. At one point, parts of the town were accessible only by boat. This illustrates how an extreme event can exceed the level of protection that existing defences provide.

Why Babet brought such severe flooding

A strong jet stream helped steer Babet towards the UK. Warm North Atlantic sea-surface temperatures supplied warmth and moisture, while low pressure encouraged unsettled conditions. Crucially, a blocking area of high pressure over Scandinavia prevented the storm from clearing eastwards quickly. Heavy rain and strong winds therefore persisted.

The wettest areas of eastern Scotland received 150–200 mm of rain, with some locations experiencing around two months’ rainfall in two days. Earlier October rainfall had already left conditions very wet. With little capacity remaining in the ground to absorb more water, additional rainfall increased runoff into rivers. River levels rose and flood defences were overtopped.

Babet also produced powerful winds. A gust of 77 mph at Inverbervie in eastern Scotland shows that this was a combined rain-and-wind hazard, not simply a river flood.

Social, economic and environmental impacts

Social impacts concern people and their wellbeing. Seven people died during Babet. Flooding forced residents from their homes, leaving some needing temporary accommodation. An estimated 1,250 properties in England were flooded, while schools across Angus closed. These effects disrupted everyday life as well as threatening safety.

Economic impacts concern costs, income and economic activity. Floodwater damaged buildings, businesses and infrastructure. The A90 between Forfar and Brechin closed after a bridge was damaged, disrupting journeys and the movement of goods. Around 100,000 customers initially lost power, interrupting households and business operations.

Agriculture was also affected. Flooded fields damaged existing crops and prevented farmers from harvesting or planting. The consequences therefore extended beyond the storm itself: interrupted work could reduce later yields and farmers’ income.

Environmental impacts concern ecosystems and physical surroundings. Flooding displaced wildlife and damaged habitats. Sewage overflows and agricultural runoff polluted water, while erosion carried topsoil from exposed fields into watercourses. Heavy rainfall also caused landslides in some areas, damaging natural habitats.

The categories overlap. A power cut is a social problem for residents but also an economic problem for a business unable to operate. What matters is explaining the consequence, not merely assigning a label.

How management reduced risk

Management worked at several stages: preparing before the storm, protecting communities during it, and supporting recovery afterwards.

Forecasts and warnings provided preparation time. The Met Office issued two red warnings for persistent heavy rain in eastern Scotland, alongside amber and yellow warnings elsewhere. These allowed authorities and residents to prepare for dangerous conditions. The Environment Agency’s flood-warning service sent over 300,000 messages by email, telephone and text during the event.

Flood protection and emergency action reduced exposure. The Environment Agency deployed protective measures and pumps, including 20 high-volume pumps across several sites. An estimated 96,000 properties were protected as part of its response. Local authorities and emergency services organised responses to the storm and its aftermath.

Financial support aided recovery and future resilience. Flooded households could apply for up to £500 towards immediate costs, while eligible small and medium-sized businesses could apply for recovery grants of up to £2,500. Flood-hit property owners could apply for up to £5,000 to make homes and businesses more resilient to future flooding.

These measures reduced harm, but did not remove the hazard. Warnings cannot stop rainfall, and protection can be overwhelmed, as happened in Brechin. Recovery grants help people rebuild; resilience measures aim to reduce damage when flooding happens again.

Is UK weather becoming more extreme?

A single event such as Babet demonstrates what extreme weather can do, but does not prove that extremes are becoming more common. Assessing change requires long records and comparisons between periods.

The Met Office’s 2025 State of the UK Climate assessment, drawing on observations from several hundred weather stations, provides strong evidence of changing temperature and rainfall extremes.

Extreme heat is becoming more frequent. Comparing 2015–2024 with 1961–1990, the number of days with temperatures 5°C above the 1961–1990 average doubled. Days 8°C above average trebled, and days 10°C above average quadrupled. These are changes in the frequency of unusually hot days, not increases of 5°C, 8°C or 10°C in average UK temperature.

Very wet conditions are also becoming more frequent. In 2015–2024, the number of months in which counties recorded at least twice their 1991–2020 monthly average rainfall increased by over 50% compared with 1961–1990. The UK’s October–March half-year was also 16% wetter in 2015–2024 than in 1961–1990. October 2023–March 2024 was the wettest winter half-year recorded for England and Wales in a series extending back over 250 years.

Not all extremes show the same trend. The frequency of the coldest nights has fallen, and the number and severity of snow events have declined since the 1960s. Observations do not currently show that the UK is becoming windier or stormier.

The strongest conclusion is therefore that UK weather is becoming more extreme in important respects, especially heat and heavy rainfall, rather than that every hazard is increasing. Rainfall remains highly variable between years and places. Long-term evidence is more persuasive than a list of recent storms, and changing extremes strengthen the need to adapt homes, infrastructure and emergency planning.

UK hazards

• Heavy rain and flooding; strong winds and coastal flooding; snow, ice and severe cold; heatwaves and droughts.
• Heatwave = unusually high temperatures. Drought = prolonged unusually low rainfall.

Storm Babet, 18–21 October 2023

Causes: strong jet stream; warm North Atlantic waters; low pressure; Scandinavian high-pressure block prolonged the storm. Earlier rain left ground very wet, increasing runoff.

Key evidence: 150–200 mm of rain in the wettest parts of eastern Scotland; River South Esk overtopped defences in Brechin.