More than 150 people are killed or injured in Snowdonia every year

More than 150 people are killed or injured in the mountains of Snowdonia every year - the majority of whom live outside the area.

Mountain rescue experts have issued advice to walkers who plan to visit the mountains over the festive period.

The guidelines urge hillgoers to plan their days, take proper equipment and be prepared to turn back if necessary.

They have been published by North Wales Police, the Mountain Rescue Association and the Snowdonia National Park Authority.

A study of mountain rescue statistics from the past five years shows that 82% of the casualties in Snowdonia were from outside the national park and Wales - the majority from the south and north-west of England.

MOUNTAIN SAFETY ADVICE Plan your walk properly Have the proper equipment and know how to use it Be prepared to turn back if the weather gets worse Seek advice from experienced mountaineers Take advantage of the Met Office Mountain weather

Men between the ages of 21 and 30 were most at risk of having an accident, the research also found.

Chris Lloyd of Ogwen Valley Mountain Rescue Team said while he had not been called out on Christmas Day in recent years, his colleagues' services were often required on Christmas Eve and Boxing Day.

"It's a bit of a pain because we're trying to have family activities," he said.

"We do ask people on the mountains to take care, because we like to have a break ourselves."

He said cold temperatures over the next few days could create "lethal" conditions over Christmas.

Aled Taylor, of Snowdonia National Park, said: "We are fortunate in having more than our fair share of beautiful country and this, together with easy access to the mountains, makes the national park a big attraction for walkers and climbers.

Getting to the top is optional but getting back down is mandatory... Mountain rescue mantra

"The weather on the hills can change completely in a short space of time. Too many walkers venture out without proper clothing and equipment and fail to take account of the risks involved, particularly in winter.

"Many accidents that happen are due to a slip or a stumble late in the day - frequently on the way down the mountain."

Mr Taylor said it was "vitally important" that people taking to the hills in winter were equipped with a map and compass - and knew how to use them.

An ice axe and crampons were also essential in snowy and icy conditions, he added.