CAULDRON OF SPRAY
WALKERS and climbers scrambled for cover when violent gusts lashed Snowdonia.
Videos shared on social media showed how Llyn Idwal was turned into a seething cauldron of spray with white-capped waves by winds sweeping down from the Glyderau, the weekend before last.
One mountain leader, a former Royal Marine Commando, described how winds “on an epic scale” forced his party to run for shelter in between gusts.
Another said the conditions were unusual as wind speeds failed to drop as his party descended to Llyn Ogwen.
“As a rule of thumb, it’s usually twice as windy on the summits as it is down in the towns below,” said Glyn Calland, who runs Gradient Adventure from Brynrefail, Caernarfon.
“But on that day it was gusting at strong at the top as it was on the bottom.”
Throughout Saturday, gusts of 80km/hour were recorded in Snowdonia, peaking at 100km/hour (62mph) at 7pm.
Glyn, a veteran of countless climbs in Snowdonia, said the wind speeds he witnessed at the weekend were strong but not exceptional.
However the conditions created a phenomenon likened to a “waterfall of wind”.
Often Llyn Idwal is sheltered by the amphitheatre of mountains that surrounds it – but atmospheric “rotor” winds can develop in the lee of Glyder Fach, creating downward columns of air. To some extent, the area is cocooned from the weather,” said Glyn.
“But you can get rotors developing, which cause the wind to plunge down the mountainside and hit the lake below. From there, it spreads out. On the lake itself you can see waves of spray coming towards you, which at least gives you some kind of warning.
“It’s why, on days like that, I would never go close to cliff edges as you can easily get knocked off.”
Other climbers in the area reported how they struggled to cope with
Saturday’s winds.
“It sent me flying a couple of meters,” said one person. “We could not stand, sometimes needed to duck for a few seconds.”