Storms
| Impact | 5 |
|
|
|
|
|
|||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4 |
|
|
|
|
|
||||||||||||||||||||||||||||||||||||||||||||||
| 3 |
|
|
|
|
|
||||||||||||||||||||||||||||||||||||||||||||||
| 2 |
|
|
|
|
|
||||||||||||||||||||||||||||||||||||||||||||||
| 1 |
|
|
|
|
|
||||||||||||||||||||||||||||||||||||||||||||||
| 1 |
2 |
3 |
4 |
5 |
|||||||||||||||||||||||||||||||||||||||||||||||
| Likelihood | |||||||||||||||||||||||||||||||||||||||||||||||||||
| ID | 48 |
|---|---|
| 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
Climate change has already altered the risk of certain types of extreme weather in the UK, with evidence suggesting that the frequency and intensity of storms is likely to increase in the future. The UK has experienced several severe storms over the last few years, including Storm Eunice in 2022, which brought gusts in excess of 100mp. The impacts of the storm across the UK included 3 fatalities, school closures, power cuts and nationwide cancellations of transport services.
Scenario
The reasonable worst-case scenario is based on storm force winds affecting multiple regions of the UK for at least 6 hours during a working day. Most inland, lowland areas would experience mean (average) wind speeds in excess of 55mph, with gusts in excess of 85mph. Although the storm would be over in less than a day, disruption to infrastructure including power, communications, transport networks, homes and businesses could last for 1-4 days and for more than 5 days in remote rural locations.
There would likely be some casualties and fatalities, mainly due to falling trees, structures or other debris. Some environment and economic impact would also be expected, due to fallen trees and disruption to transport networks.
Key assumptions
This risk is based on historical events, primarily combining the impacts of the October 1987 and Burns Day 1990 storms. The likelihood of these events varies, with northern areas more likely to be affected.
Variations
In a variation, wind strengths may be less, but from a direction other than the prevailing westerly/southwesterly. This may bring additional hazards (for example snow) and vulnerabilities to trees and infrastructure.
Response capability requirements
The Met Office National Severe Weather Warning Service provides warnings for severe weather (including wind) up to 7 days ahead of it affecting the UK. This service gives advance warning of storms and enables individuals and organisations to plan and mitigate against the potential impacts ahead of the severe weather.
Recovery
For most of the impacts in this scenario, recovery would take place over several days, but could take longer in some instances once the storm has passed. Power and communications supplies to affected rural areas may be last to be restored. There may, however, be some long-term, even permanent, impacts to the environment, as trees and habitats that have been destroyed by the storm could take a long time to become re-established.