Firefighters were brought in to control the flames
Property could be damaged, and someone seriously injured, if maliciously started gorse fires get out of control, a councillor has warned.
Cadfan Roberts spoke out after an acre of common land was set ablaze near his home in Carmel in Gwynedd on Thursday.
The community councillor said flames were an annual problem which got close to a number of properties.
North Wales Fire and Rescue Service warned earlier in the week that these types of fires stretched resources.
"We have problems with this mountain every year," said Mr Roberts.
Mr Roberts said there was concern locally that the fires could affect nearby properties.
"It depends where the fire is started, and the direction of the wind, but there are properties on both sides.
"Someone walked up onto the hill to do this, but luckily this time we had a few heavy showers of rain," he added.
North Wales Fire and Rescue Service said five appliances, and one off-road vehicle, was sent to Carmel on Thursday to deal with the fire.
Mr Roberts said: "Various people have grazing rights there... as it is common land.
"But as there are sheep up there now, it is unlikely that anyone who has grazing rights would start this fire."