It's when the temperature rises and the sun shines. Rows of deckchairs appear outside the piste-side restaurants, faces develop that tell-tale souvenir of panda eyes, the snow is slushy by lunchtime, and scores of ski bums begin to feel a little knot of anxiety deep inside as they realise that the "real world" is calling them back to the 9 to 5.
Fortunately, just as the posters have gone up for the end of season barbecues, winter returns. Snow starts falling and the general whoop of joy and excitement is drowned out in the rush to dig out the powder skis and get to the first lift.
It looks like we've reached that point of the season. After a week of warmth, with double digit temperatures and brown patches of earth appearing on the lower slopes, snow, and lots of it, is forecast in the Alps for today, tomorrow, and possibly much of next week.
Netweather, one of the most reliable weather websites, is forecasting snow across French, Swiss and Austrian resorts for most of the weekend with more during the course of next week. Bring it on!