A Status Red wind warning has been issued for counties Cork, Kerry and Clare, with "severe and damaging gusts" forecast by Met Éireann.

With Storm Barra hitting Ireland, all other counties across the country face either a Status Orange or Status Yellow.

Each warning carries with it different levels of advice for people to adhere to, ranging from simply being aware of the impending weather, to people taking active action.

Met Éireann says the core rationale for issuing such warnings is to protect people's lives and livelihoods, as well as to mitigate damage to property and any disruption to economic activity.

How is each warning categorised? And what does Met Éireann take into account when issuing them?

(File image: Rolling News)

Status Yellow:

Under Yellow alerts, people are urged to "Be Aware".

Met Éireann says it is implicit that Status Yellow warnings are for weather conditions that "do not pose an immediate threat to the general population".

The aim behind them is more so to notify those who may be exposed to risk because of their location or activity, and allow them take preventative action.

These are usually used for "not unusual weather" or localised danger.

Status Orange:

Under Status Orange alerts, people are urged to "Be Prepared".

This level of alert is issued by the forecaster for conditions which have the capacity to "impact significantly" on people in affected areas.

Met Éireann says that the issuing of an Orange level alert implies that "all people in the affected areas should prepare themselves in an appropriate way" for the anticipated conditions, and check any activities they may "delay or cancel as appropriate".

These are used for weather which is infrequent, as well as potentially "dangerous or disruptive weather conditions which may pose a threat to life or property".

Status Red:

The big one – under Status Red alerts, people are urged to "Take Action".

Met Éireann says that the issuing of a Status Red alert should, under normal circumstances, be a rare event. They are classed as "very dangerous weather conditions from intense meteorological phenomena".

Status Red means that those in affected areas should take active actions to protect themselves and their property.

The forecaster says this can be done by moving families out of a danger zone temporarily, staying indoors, or taking other means by which to mitigate the effects of incoming heavy weather conditions.

During a Status Red warning, people are urged to follow instructions and advice given by authorities, and "be prepared for exceptional measures".

Met Éireann head of forecasting Evelyn Cusack said yesterday morning the storm will bring a "danger to life, a risk of flooding, as well as risk of snow".

(File image: Rolling News)

Met Éireann issues weather warnings whenever weather conditions meeting certain detailed thresholds are anticipated within a 48-hour period.

A judgement is then required on the part of the forecaster who must weigh up the possible severity of the weather conditions, as well as the likelihood of their occurrence.

However, Met Éireann says on some occasions such as weekends, and during holiday periods, it may be necessary to issue warnings beyond 48 hours.

What criteria is used to gauge the level of a warning?

For Status Red:

Mean wind speeds in excess of 80km/h and gusts in excess of 130km/h would lead Met Éireann to issue a red level wind warning.

For a Status Red rainfall warning, the anticipated rainfall would have to meet the threshold of over 40mm in six hours, 50mm in 12 hours, or 70mm in 24 hours.

For a Snow/Ice warning, significant snowfalls leading to accumulations of over 8cm, as well as treacherous paths and roads due to ice or untreated surfaces would lead to a warning here.

For Status Orange:

Mean wind speeds of between 65-80km/h and gusts of between 110-130km/h would lead Met Éireann to issue an Orange level wind warning.

For a Status Orange rainfall warning, the anticipated rainfall would have to meet the threshold of 30-40mm in six hours, 40-50mm in 12 hours, or 50-70mm in 24 hours.

For an Orange level Snow/Ice warning, it is also as above, however with accumulations of over 3cm rather than 8cm.

For Status Yellow:

Mean wind speeds of between 50-60km/h and gusts of between 90-110km/h would lead Met Éireann to issue a Status Yellow wind warning.

For a Status Yellow rainfall warning, the anticipated rainfall would have to meet the threshold of between 20-30mm in six hours, 25-40mm in 12 hours, or 30-50mm in 24 hours.

For a Status Yellow level Snow/Ice warning, once again it is as above, however with accumulations of less than 3cm.