Imagine you are caught in an avalanche. You are buried under two metres of snow. Your friends (if alive) don't know where to start looking.
The first thing that comes to mind is infrared cameras. Used by police and rescue teams across the world, infrared cameras can detect human body heat under debris.
If buried in an avalanche, a human body would not register on the camera
In the Scottish highlands, infrared cameras are already being used to track people lost in the wilderness. It allows them to spot casualties that might be stuck in steep dangerous rocky ground at night - without putting the rescue teams themselves at risk.
After the avalanche tragedy in the Alps yesterday, you might think this is something ski patrol should be using regularly.
However there is one major flaw. Thermal imaging works by relying on surface temperature to find victims. If buried in an avalanche, a human body would not register on the camera.
If something small was sticking out of the snow - say a human finger or foot - then using an infrared thermal camera could be very useful.
Plenty of studies have looked into this matter - including the idea of using drones equipped with thermal cameras to fly over avalanche zones to spot buried bodies.
These cameras are very heavy and very expensive. Unfortunately, studies have shown that long wave infrared heat detection was impossible, even under a thin layer of snow.
While infrared thermal imaging could be useful for finding missing people in a white out for finding missing people or lost above ground, it might be a while before scientists develop technology to find people under 3 metres worth of snow.