Hundreds of cars have been parked along mountain roads in Snowdonia, reducing traffic to single file in places.
Parking tickets have been issued to some vehicles parked along the A4086 around Pen-y-Pass – the closest car park to the summit of Snowdon.
Snowdonia National Park Authority warned visitors that many car parks were full and urged visitors not to park on roadsides.
Gwynfor Coaches said its services were struggling to get through.
“People who live in a city think we’ll go up a mountain, it’ll be quieter than where we are,” a local worker said.
“But when thousands of people have the same idea that goes out the window.”