Low temperatures and snow
| Impact | 5 |
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| 2 |
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| Likelihood | |||||||||||||||||||||||||||||||||||||||||||||||||||
| ID | 50 |
|---|---|
| Risk theme | Natural and environmental hazards |
Impact & Likelihood
| 5 | Catastrophic |
|---|---|
| 4 | Significant |
| 3 | Moderate |
| 2 | Limited |
| 1 | Minor |
| 5 | >25% |
|---|---|
| 4 | 5-25% |
| 3 | 1-5% |
| 2 | 0.2-1% |
| 1 | <0.2% |
Background
Winters with low temperatures and heavy snowfall pose a significant threat to human welfare, essential services and the economy. In late February and early March 2018, the UK experienced a spell of severe winter weather with very low temperatures and significant snowfall. This event became known as ‘The Beast from the East’ in the media and led to widespread impacts across the UK, including disruptions to transport services, school closures and power cuts.
Scenario
The reasonable worst-case scenario is based on snow falling and lying over multiple regions of the UK and a substantial proportion of the UK population, including substantial areas of low-lying land (below 300m), for at least one week. After an initial fall of snow, there would be further snow fall on and off for at least 7 days, with brief periods of freezing rain also possible. Most lowland areas would experience some falls in excess of 10cm at a time, a depth of snow in excess of 30cm for a period of at least 7 consecutive days with daily mean temperature below minus 3°C. Overnight temperatures would fall below minus 10°C in many areas affected by snow.
Such a spell of weather would affect vulnerable communities, particularly older people and those with pre-existing conditions (for example cardiovascular/respiratory disease). An increase in falls, injuries (for example fractures), road accidents and hypothermia would also be expected. There would be excess deaths, above what is experienced in a normal winter, with a significant number of casualties and fatalities, placing significant pressure on health and social care services. Considerable impact to essential services, along with economic impact, would be likely due to disruption to transport networks, power or heating fuel supplies, telecommunications and water supplies. Schools and businesses would also be impacted by such disruption.
Key assumptions
The risk assumes that all types of impact experienced during previous cold and snow events are likely to occur during such a spell of weather described in the risk. High level and rural communities are likely to be affected for longer by snow than lower altitude towns and cities.
Variations
Severe snow/cold events could be longer, cover more low-lying land, and be accompanied by significant drifting. An event affecting the rest of Europe could affect supply chains.
Response capability requirements
The Met Office National Severe Weather Warning Service provides warnings for severe weather (including snow) up to 7 days ahead of it affecting the UK. This service gives advance warning of snow and ice and enables individuals and organisations to plan and mitigate against the potential impacts ahead of the severe weather.
The Heat-Health Alert System will transition to impact-based alerting for summer season 2023, with the Cold Weather Alert system following in winter 2023/2024. The alerts will be issued by UKHSA in collaboration with the Met Office, with users needing to register for this new alerting system.
The UK Health Security Agency has launched the Adverse Weather and Health Plan (AWHP) as part of a commitment under the National Adaptation Plan to bring together and improve existing guidance on weather and health. The AWHP brings together the previous Heatwave Plan for England, first published in 2004, and the Cold Weather Plan for England.
The plan builds on existing measures taken by the government, its agencies, NHS England and local authorities to protect individuals from the health effects of adverse weather and build community resilience.
Recovery
Longer-term impacts from low temperatures and heavy snow are not anticipated. Where low temperatures and snow lead to secondary impacts such as an increase in the likelihood of utility system failures or flooding due to snowmelt, recovery due to these secondary impacts may take longer.