I'm a keen skier, and I've often been happily surprised by snow fall despite temperatures of 1 or even 2 °C. After some research I found that the explanation relies in assuming that these above freezing temperatures are confined to a layer close to the surface as explained here: https://www.onthesnow.com/news/a/15198/can-it-snow-when-temps-are-above-freezing
However, today I saw the same phenomenon on a ski resort that reports temperatures at different heights, suggesting that the above freezing temperatures extended by at least a kilometer from the base. However, there were fluffy snowflakes falling anyways.
How can that happen?