Walkers, climbers and backcountry skiers have been warned to prepare for potentially challenging conditions in Scotland's hills and mountains.
Mountaineering Scotland said winter was "back with a vengeance" after unseasonably warm weather last month.
The organisation has warned of the change in conditions following the deaths of three climbers in an avalanche on Ben Nevis on Tuesday.
The slide occurred above the men as they were climbing in a gully.
Two of the three climbers who died were from France and the other from Switzerland.
The only survivor of the accident was Swiss. He has been receiving treatment in hospital in Glasgow.
Mountaineering Scotland, which represents the interests of outdoor pursuits enthusiasts, said February's warm weather had almost caused a complete loss of the snowpack in the hills and mountains.
But it said there had since been a sudden and heavy snowfall, combined with lower temperatures and high winds.
The Met Office has issued a yellow "be aware" warning for snow for parts of Scotland on Saturday.
Also, in the space of 48 hours over Wednesday and Thursday, five avalanches were recorded in the west Highlands by the Scottish Avalanche Information Service.
The service provides information on the potential avalanche risk in six areas: Creag Meagaidh, Lochaber, Glen Coe, Torridon and the Northern and Southern Cairngorms.
Mountaineering Scotland said it wanted to encourage walkers, climbers and backcountry skiers to "temper" their enthusiasm for the winter conditions by paying "close attention to avalanche and weather forecasts".
Heather Morning, mountain safety adviser, said: "Mountain conditions in February were unusually mild, resulting in the majority of the mountains being snow free.
"However, over the past few days winter has very much returned.
"When you're heading up into the hills, whether it's for walking, climbing or skiing, it's absolutely essential not only that you check the avalanche forecast but also that you understand what it's saying. Different slopes on the same hill may have completely different snow conditions."
She added: "A careful study of the mountain weather forecast is also an essential part of your planning, and your planned route should be finalised with that forecast in mind.
"Something else to be mindful of is being flexible. Don't become fixated on achieving your original goal. As conditions on the hill change, then so should your decision-making.
"Often I end up on Plan B, C or D as my journey on the hill progresses."