Rescue teams say ice picks and crampons are essential on the peaks
A mountain walker suffered head and leg injuries when he decided to slide 150ft (45.7m) down an ice sheet in Snowdonia because it was "easier than walking".
The 23-year-old, from Stockport, Greater Manchester, had to be rescued off Tryfan by an RAF helicopter crew on Monday afternoon.
He was taken to Glan Clwyd Hospital in Bodelwyddan where he was treated for head injuries and a cut to his leg.
Three people were airlifted to safety in two separate incidents on Monday.
The man who slid on Tryfan was with a woman companion, who also tumbled but only about 50ft (15.2m). She was flown to hospital where she was treated for a suspected broken ankle.
Chris Lloyd, of the Ogwen Valley Mountain Rescue team, said the pair decided to slide down the mountain because they thought it would be easier than walking.
He said: "They couldn't climb down because the weather was awful and they didn't have the right equipment.
"They are very, very lucky indeed."
The team has seen the number of rescues in Snowdonia double and a major campaign has been launched by the emergency services to encourage people to think carefully before they climb one of the 3,000ft (914m) peaks.
Winds can reach 150mph and temperatures can plummet to -20C.
The Ogwen Valley team, one of three rescue units in Snowdonia, has carried out more than 130 rescues alone so far this year.
On Monday, a man aged in his 40s, and believed to be local to the area, suffered a broken ankle on Y Garn and had to be airlifted to hospital in Bangor.
On Sunday, a father and son trapped on Y Garn were saved by an unknown passer-by who alerted rescuers by mobile phone.
The pair, aged 49 and 24, from Wirral, Merseyside, had strayed on to steep ground below the East Ridge of the mountain when the younger man lost his confidence and was unable to move any further.
They were airlifted to safety by an RAF search and rescue helicopter from Valley on Anglesey.
Mr Lloyd said: "People should remember the weather is very bad on these mountains and they should have the right clothing and the right equipment and the right experience."
There have been several deaths so far in 2009, although officials say the number is no higher than previous years.