UK snow: What is a level 3 cold weather alert?

A level 3 cold weather alert has been issued for the whole of England after temperatures plummeted this week and parts of the country were pummelled by snowy showers.

The snow has caused travel chaos across the UK, with flights at some airports grounded or delayed, travel warnings on the roads and widespread problems on rail networks.

The Met Office has issued three amber warnings for “strong winds bringing blizzard conditions” and up to 16in (40cm) of snow for an area stretching from Stoke-on-Trent to Durham, as well as North Wales and Northern Ireland.

“Significant disruption” to transport including flights, power lines and phone network coverage is likely in the regions covered by the warnings.

The amber snow alert for England lasts for 21 hours from 3pm on Thursday and covers major cities including Liverpool, Sheffield, Bradford and Leeds.

Over Wales, the amber snow and ice warning is in place from noon until 9am on Friday, stretching from the north coast to Radnorshire.

The amber snow and ice warning in Northern Ireland covers Belfast and areas south of the city from 3pm on Thursday until 4am on Friday.

Heading into Friday, the Met Office predicts that the snow will clear in the East of England, although snow showers are expected to persist in northern Scotland.

The UK Health Security Agency (UKHSA) said: "As of Wednesday 8 March, the level 3 cold weather alert issued by the UK Health Security Agency (UKHSA) has been extended until 9am on Monday 13 March."

Dr Agostinho Sousa, head of extreme events and health protection at UKHSA, said: "During periods like this, it is important to check in on family, friends and relatives who may be more vulnerable to the cold weather, as it can have a serious impact on health.

"If you have a pre-existing medical condition or are over the age of 65, it is important to try and heat your home to at least 18C if you can."

National Highways has also warned drivers in the West Midlands and the East of England not to travel unless their journey is essential.

But what is a Level 3 cold weather alert?

Cold weather alerts are ranked from levels 1-4 depending on the severity of the weather and how long it is expected to last.

Level 1 (green) is "the minimum state of vigilance during the winter", whereas the highest level 4 (red) is described as a "national emergency" that is "reached when a period of cold weather is so severe and/or prolonged that its effects extend outside the health and social care system".

At level 4, "the health effects may occur among the fit and healthy, and not just in high-risk groups", according to UKHSA.

The level 3 warning that is currently in place across England, and is expected to remain in place until after the weekend, means there is a "mean temperature of 2C or less and/or widespread ice and heavy snow" and "alerts social and healthcare services to take specific actions to help protect high-risk groups".

Alongside the warning is suggested action for people to take, advising them to "look out for friends and family who may be vulnerable to the cold, and ensure they have access to warm food and drinks and are managing to heat their homes adequately."

Additionally, under a level 3 warning, people should "try to maintain indoor temperatures to at least 18C, particularly if you are not mobile, have a long-term illness or are 65 or over".

"Avoid exposing yourself to cold or icy outdoor conditions if you are at a higher risk of cold-related illness or falls and stay up to date with the latest weather forecasts on the Met Office website", the Met Office added.