CSC’s Schleck, who trailed Evans by one second going into the 15th stage from Embrun, takes a seven-second lead in the general classification from Bernhard Kohl, who headed home the chasing pack behind the breakaway group.
Kohl, of Gerolsteiner, finished fifth in the stage ahead of Schleck, ninth, and the Austrian has a one-second advantage over Evans, who drops to third overall.
As Evans toiled in yellow, his fellow Australian Simon Gerrans rode the perfect ascent up Prato Nevoso to outfox his fellow escapees and win the 183km stage by three seconds from Egoi Martinez.
The 28-year-old Credit Agricole rider sat on the wheel of Danny Pate and Martinez, and kicked away in the final metres.
Martinez, King of the Mountains at the 2006 Vuelta a España, appeared in the box seat when the trio entered the last 300m of the 11.1km climb to the Italian ski station, but he could not respond when Gerrans moved.
The escapees benefited from several crashes in the peloton, most notably to third-placed Christian Vandevelde, and 2006 Tour winner Oscar Pereiro, who was forced to retire with a broken femur and shoulder.
Evans was isolated from his Silence-Lotto team and worn out by the pace set by Schleck’s younger brother Andy, and he was fortunate to escape greater losses on the Tour’s first day in the Alps.
One of his main rivals, Denis Menchov, kicked clear of the yellow jersey group 7km from the summit, only to slip on the apex of a corner.
The Rabobank rider remounted and rejoined the group, coming home in eighth, 20 seconds behind Kohl, but his challenge for yellow was over for the day.
Kohl just misses out on yellow despite a powerful finish, but has the consolation of taking the polka dot jersey from Gerolsteiner team-mate Sebastian Lang.
The weather put paid to any chance of the breakaway quartet being caught, with the peloton enduring dreadful conditions on the Agnel in particular.
There were also mass falls either side of a roundabout approaching Cuneo, with Christian Vandevelde, Damiano Cunego and Briton David Millar all appearing to slip on a substance.
Vandevelde continued without much of a problem and caught up with the maillot jaune to finish 10th and stay in touch.
The trouble encountered by the riders served to justify Team Columbia’s decision to withdraw Mark Cavendish.
The Isle of Man star was pulled from the Tour in the morning before the stage, citing fatigue and the need to prepare for the Madison track event in the Beijing Olympics.
In doing so, Cavendish, 23, turned down the opportunity to become the first man to win five stages in a Tour since Lance Armstrong in 2004.