Police are appealing to visitors to south Wales’s highest peak to park sensibly at the weekend.
The winter Fan Dance Races take place over Pen y Fan on Saturday and Sunday and high numbers of visitors are expected.
Dyfed-Powys Police said during last year’s event cars parked on the side of the road in the Brecon Beacons national park area caused substantial difficulty to emergency services vehicles, which were called to a three-vehicle collision, and created a hazard to pedestrians who had to walk in the road.
The Storey Arms area on the A470 was particularly affected.
A police spokesperson said: “With the forecast snow and the Fan Dance event continuing this weekend police are preparing for an influx of visitors to the area and are urging anyone thinking of coming to the Brecon Beacons to firstly consider whether the journey is necessary and safe and secondly to park responsibly.”
Sergeant Owen Dillion, of the roads policing unit, said: “This weekend there will be a police presence around the Storey Arms area as we endeavour to ensure people are parking responsibly, and we will be taking action against those breaching the clearway.
“We are also encouraging people to look at alternative routes up Pen y Fan to avoid congestion around the A470 and asking them consider if the journey is really necessary or safe.
“The area is a national park and much of the Storey Arms section of the A470 is a clearway which means that roadside parking is not permitted.
“Past parking issues we’ve experienced in the area created associated risks for pedestrians moving to and from their vehicles, in addition to potential conservation issues caused by damage to roadside verges.
“Last January we issued fines to over 100 vehicles parked illegally in one weekend. We really hope not to do the same this year.”
The Fan Dance Races are a series of endurance events which follow the route over both sides of the 886m (2,907ft) mountain, traditionally used as part of the selection process for military special forces. The events are organised by former members of the Special Air Service and Special Boat Service and include both winter and summer races, carrying full-weight rucksacks.