The road is blocked between Ballyvary and Straide after a bus got into difficulties due to the treacherous conditions.

UPDATES: Mayo brought to a standstill by heavy overnight snowfall

Mayo has been brought to a standstill this morning by a heavy fall of overnight snow leading to treacherous road conditions.

Many roads are impassable and outdoor teams employed by Mayo County Council are seeking to deal with the situation.

Gritting crews have been out with ploughs where possible.

A council spokesperson said: "Please assume that road conditions will be difficult and avoid unnecessary journeys.

An aerial view of Claremorris. Photo: Darragh Delaney

There are several reports of cars, buses and trucks getting into difficulty and leading to delays or diversions for other road users.

The Ballyvary to Straide Road is closed after a bus got into difficulties due to the conditions.

The Old Glenisland Road is closed to traffic as is the Windy Gap route between Castlebar and Bofeenaun.

Trees down across the road on the Manulla mountain. Photo: Kathy Lyons

A substantial volume of snow is reported on routes around Westport, Castlebar, Claremorris, Mulranny, Ballycroy and Bangor.

The N5 between Castlebar and Westport is in a dangerous condition.

The R312 at Keenagh, near Glenisland, is impacted by fallen trees.

The morning train service between Westport and Dublin was delayed by 45 minutes.

Snow began to fall in Castlebar last night shotly after 8 p.m. and accumulated rapidly, leading to problems for motorists trying to navigate roads with any gradient.

A car stuck at the top of Rock Square/Castle Street in Castlebar.

While snowfall has eased off, more is forecast later this morning.

Gardaí in Mayo say a number of trees were toppled by the volume of snow that fell overnight.

A significant number of schools throughout the county are closed because of the conditions and due to the fact the school bus services are not running.

A snowman on Market Square, Castlebar.

Power outages have been reported by the ESB in Swinford, Castlebar, Achill, Westport, Kiltimagh, Knock, Glenhest, Balla and Ballyhaunis.

Castlebar Social Services Bus and Day Centre have been cancelled today in the interest of safety.

Mayo County Council is reporting that power and communications overhead cables are hanging low due to the showfall build-up on lines.

High-sided vehicles are urged to exercise extreme caution.

The election campaign has also been brought to a halt with canvassing teams getting a well-earned rest ahead of the final week.

Impact to health services in Mayo due to dangerous road conditions

Please be advised that heavy snow and ice overnight has led to treacherous road conditions across county Mayo.

Access routes to Mayo University Hospital and many community based health services are significantly impacted.

Please do attend the hospital unless it an emergency.

MUH is focusing today on emergency care, unfortunately some elective procedures and OPD appointments will be postponed.

If you have an appointment in a HSE community healthcare setting in Mayo please only travel for your appointment if it is safe to do so.

People advised to avoid unnecessary journeys

The Road Safety Authority has advised people to avoid any unnecessary journeys in areas under an Orange alert and to exercise extreme caution if you do have to go out.

Public Relations Officer David Martin advised drivers to clear all snow and ice from their vehicles before setting off.

He said drivers need to slow down because it takes longer to stop on snowy or icy roads, adding that it will remain icy for at least the next 24 hours.

Speaking to RTÉ's Today with Claire Byrne, he warned that black ice is one of the biggest hazards in winter.

"Slow down, and if you are in a skid, don't brake," he advised.

"Take your foot off the accelerator and use your controls to slow yourself down."

Mr Martin said that as the snow turns to rain later this week there might be flooding on the roads.

He advised drivers not to try and drive through flooded roads as the water is often a lot deeper than it appears to be.

He also advised cyclists and pedestrians to wear high visibility clothing and urged drivers to be aware of them.

Show hits radio transmitters

The snow has hit Midwest Radio's FM frequency but listeners can still tune in via their mobile phones or laptops.

The FM frequency for RTÉ's radio stations is also impacted.

Status Yellow low temperature/ice warning updated

A Status Yellow low temperature/ice warning has been updated to a nationwide alert.

It has also been extended to 12 noon on Friday.

The possible impacts are hazardous conditions on roads and footpaths and some travel disruption.