A woman has died and two others have been rescued while tramping in the Nelson Lakes National Park this weekend.
A helicopter and police were dispatched after receiving a report of a severely hypothermic woman at high altitude on Sunday morning.
The 55-year-old woman was already dead when she was located on Mount Robert Ridge.
The police confirmed the woman was tramping with a family member and said victim support services have been provided.
In a separate incident, two trampers were rescued by helicopter on Saturday night after encountering deep snow on the same ridge.
They found a small pocket of phone coverage and called 111 late in the afternoon.
The Nelson Rescue Helicopter set off in the fading light.
Using night vision goggles, the helicopter crew spotted the trampers' headtorches and lifted them to safety.
Search and Rescue coordinator Sergeant Malcolm York said it was important to monitor weather conditions before setting out.
In both incidents the parties began their trips into exposed, snow-covered alpine routes in inappropriate weather conditions with snow falling and the wind chill plummeting down to -16 degrees, he said.
"It is important to monitor proposed weather conditions and make good decisions around them, and the risk that inclement weather poses to your intended trip.
"Consider the time of day you are setting out, know your limitations and make sure you have appropriate clothing and equipment with you."
The police have issued advice for trampers, saying a personal locator beacon should always be taken on back country routes.
Follow the Outdoor Safety Code:
- Plan your trip
- Tell someone reliable your plans
- Be aware of the weather and make good decisions around it
- Know your limits
- Make sure you are adequately equipped for your intended trip
- Take sufficient supplies