Glyder Fawr was previously thought to be only 999m tall, too short to qualify for 'super-mountain' status. Photograph: David Roberts/Alamy
The peak of Glyder Fawr in Snowdonia has long been regarded as a poor relation to the four Welsh "super mountains" that soar over 1,000 metres. But surveyors have now revealed that the summit, believed previously to top out at a tantalising 999 metres (3,277 ft), does in fact reach the kilometre mark.
The mountain, whose name translates as "great heap", was confirmed to be 1,000.8 metres, and becomes the fifth Welsh super mountain.
There are implications for map-makers, walkers and runners. Future editions of maps will have to be altered to reflect Glyder Fawr's new status, and tourism brochures will have to be redesigned. A race taking in the Welsh peaks above 1,000 metres will be rethought and a flood of extra walkers is expected to arrive in Snowdonia to bag the fifth super mountain.
The mission to prove Glyder Fawr's height has echoes of the Hugh Grant film The Englishman Who Went Up a Hill But Came Down a Mountain, in which a cartographer is faced with the tricky challenge of telling Welsh villagers that their local mountain is actually a hill.
Ordnance Survey measures the height of a mountain using photogrammetry, which uses detailed aerial images to create three-dimensional images of the countryside. However, this method can have a margin of error of three metres.
A more detailed measurement was taken by a group of keen amateur surveyors who climbed Glyder Fawr and strapped a GPS antennae to the summit. By receiving signals from satellites, it was possible to get a more accurate measurement.
Snowdonia's director of land management, Emyr Williams, praised the group. "We now have a fifth peak in Snowdonia which is higher than 1,000 metres, and, as a result, is sure to attract more walkers to this area. It also adds another peak to the Welsh 1,000-metre peaks race. Our challenge however, following [the] announcement, is to ensure that this area's special qualities will be carefully protected."
Rhys Evans, the Snowdonia manager for the National Trust, said the new height was a "significant announcement" for the region.
"It will also provide a welcome boost to the number of visitors to the area, which will hopefully have a positive impact on the local economy," he added.
The mission to prove Glyder Fawr's height has echoes of the Hugh Grant film The Englishman Who Went Up a Hill But Came Down a Mountain, in which a cartographer is faced with the tricky challenge of telling Welsh villagers that their local mountain is actually a hill.
