Daniel, a Parisian who emigrated to his beloved mountains as a young man, was employed as a "pisteur" or avalanche expert. It was his job to know which slopes might be dangerous and, if necessary, to launch controlled avalanches with small explosions to allow the holiday-makers to ski safely.
On Tuesday all the Grands Montets slopes were closed, as they had been for seven days, partly on Daniel's advice. After a week of the heaviest snow falls anyone could remember on the Massif du Mont Blanc, the avalanche danger was at its maximum. Everyone was advised to stay indoors as much as possible.
Daniel's home was in the hamlet of Montroc, just to the east of Argentiere. When asked if he feared that avalanches might reach his modern chalet, Daniel would claim a four-fold safety guarantee. He was an avalanche expert; he had bought the chalet from an avalanche expert; the hamlet was in a "white zone", signifying minimal avalanche risk. The only known avalanche track in the area, inactive for 91 years, was on the opposite slope of the valley, on the other side of a main road and small river. To reach his home, an avalanche would have to cross both and then climb 50 metres uphill.
On Tuesday afternoon, high on the opposite slope, the Montagne de Pecleray, a terrifying natural phenomenon occurred which Daniel understood well but never expected to occur here with such ferocity. The two to three metres of freshly fallen, light powdered snow on the upper slopes of the mountain were whipped into a snowstorm by the wind. A special kind of avalanche - an "aerosol avalanche", a cross between an avalanche and a whirlwind - began to move down the north-western slope of the mountain, towards Montroc. Gathering speed and power and denser layers of snow as it fell, the avalanche snowballed to a monstrous 18 metres high and 200 metres wide - the length of two soccer pitches - before it ploughed into the tree line.
Reducing the tall firs to match-wood, the loosely packed snow cloud crashed into the valley bottom at an estimated 100mph and continued for 100 metres up the opposing slope, bulldozing three chalets and toppling and burying 15 others. Daniel, his wife and granddaughter and nine other people in neighbouring chalets were killed. His son, Raphael, was trapped, barely conscious, for 10 hours between the now densely packed snow and the remains of a concrete wall. When rescued, he was close to death but recovered enough to be told, two days later, what had happened to his home and his parents and his tiny niece.
The tragedy of the Lagarde family - a family well known and loved in the Argentiere area - helps to explain the sense of shock and fear that has settled on this small Alpine town five miles east of Chamonix. The whole town turned out for their funeral on Friday. If such a disaster could befall an avalanche expert in a no-danger zone, then no place in the mountains is safe. The entire, complex map of avalanche risk zones, the basis for the rapid development of the Chamonix valley in the last 30 years, may have to be torn up.
MICHeLE, PROPRIETOR of a small chalet hotel in Argentiere, who knew the Lagardes well, says: "Living in the mountains is like living near the sea. You grow used to the idea that you are going to lose loved ones. But you expect to lose them on the sea, or up in the mountains. You don't expect them to die in their own living-room, in front of the television or in front of the fire."
Faced with an exodus of panicked tourists, and a wave of cancellations just before the Parisian February "snow holiday" as well as the influx of British visitors arriving this weekend for the half-term holidays, business people and politicians in the French Alps are anxious. In the last fortnight, the death toll from avalanches has risen to 21. On Friday, Catherine Ovington, 26, was killed after she and four others ignored warnings from the French authorities by venturing on to treacherous out- of-bounds slopes above Val d'Isere.
The worst incident was undoubtedly Tuesday's disaster. But was it a horrific one-off; a combination of exceptional circumstances which could happen only "once in a century"? So it may prove.
Two questions must be asked, however, at least one of which may be the centre of a legal investigation. The first concerns something that even French investigative magistrates cannot subpoena - the weather. The extraordinary snowfalls in the Mont Blanc area, and throughout the Alps, in the last ten days, are the highest since recordings began in the 1950s. They are part of a disturbed weather pattern that has brought freezing temperatures to Italy and Greece and balmy weather to Iceland in recent weeks. Last winter, Alpine resorts complained because there was almost no snow.
Some meteorologists blame the confused weather on the effects of global warming. If they are right, conventional wisdom on avalanche danger in the Alps - based on the expectation of steady snowfalls and warmer periods to glue the snow together - will have to be reconsidered.
Rene Bozon, the assistant mayor of Chamonix in charge of public safety, is a leather-faced mountain guide who looks 55 but is 73. He is regarded as one of the valley's great experts on avalanches; an expertise that has been dearly bought. His father, his brother and his son were all mountain guides, and all died in avalanches; avalanches high up in the mountains, not in the valley bottoms.
Mr Bozon dismisses, cautiously, the global warming theories. "My belief, my hope, is that this is something cyclical. A period of severe weather of this kind comes along every few decades. There is no reason to believe it will become a regular pattern."
But a few decades ago - say 40 years ago - the population of the Chamonix valley, in the shadow of Europe's highest mountain, was a few hundred people. Now the permanent population is 20,000. At the height of the ski season it might be 80,000 or 100,000. Almost the entire valley has become a kind of winter-sports suburb. Only one farm survives in a valley dependent on tourism.
This brings us to the second question, one that may be the subject of a legal investigation by an examining magistrate. (The chief prosecutor for the departement visited the scene on Wednesday.) How carefully was the valley mapped for avalanche risks in the early 1980s? Did the pressure for commercial development lead some zones to be placed in the white (no risk) category, when an appreciable risk in fact existed?
Francois Giannocarro, assistant director of the Institute of Major Risks in Grenoble, says: "Put yourself in the place of a local official, who has some big business wanting to invest ... There has to come a point when a risk is negotiable."
There are three levels of avalanche risk. In the red (high risk) zones no building is allowed. There are 118 "avalanche avenues" in the Chamonix area, which fall into this category (as of last Tuesday, that should rise to 119). There are blue zones where construction is allowed under certain conditions. Buildings must have reinforced concrete walls facing the danger area; they must have small windows and avalanche defences. Evacuation is mandatory when the risk is high. In the white zones - something like 60 per cent of the valley - no building precautions or defences are required.
ASSISTANT MAYOR Bozon rejects any suggestion that the mapping of the Chamonix area was influenced by commercial considerations. He says the zones were categorised by examination of past avalanche tracks and by questioning older residents on past slides. In the case of Montroc, there had been only one serious avalanche on that slope - in 1908, and that did not breach the tree line.
"If those chalets had been built to blue-zone standards, they would not have been swept away," he says. "They would have been severely damaged, certainly. But there is every reason to believe that we would not have lost so many lives."
He insists, however, that what happened was completely unpredictable; that there was no reason to expect, at that place, whatever the prevailing avalanche risk, a slide of such terrible force and magnitude.
Daniel Lagarde evidently agreed. The fact that he, a professional expert in avalanche dangers, installed his family in Montroc tends to suggest that there was no official negligence. But is that not just as worrying? Is not the whole basis of avalanche knowledge and avalanche mapping - on which the valley has been planned - called into question?
Mr Bozon agreed it was inevitable that the entire risk map "will be looked at again".