The mountains await defending champion Lance Armstrong

There is even talk of the possibility of snow on the highest point of the stage - the finish at the Hautacam ski station.

Until now the favourites have been trying to keep out of trouble amid the mayhem of bunch sprints and breakaway winners.

France's leading rider Laurent Jalabert did briefly hold the leader's yellow jersey, but was not too upset when he lost it after two days to Alberto Elli.

On Monday all eyes will be on the Italian as he hits the first tough climbs of this year's race in the leader's yellow jersey.

Salvatore Commesso: Apprehensive about the mountains

Elli is a competent climber who may yet hang onto his jersey during this first mountain stage, but this will not be the Telekom team's major concern.

"Tomorrow we will get to the mountains and the big favorites will come through," Elli said on Sunday.

"I have already done well. It is not often the way for a yellow jersey but Jan Ullrich is the team leader and on Monday I will work for him."

Riders such as Jalabert, Ullrich, defending champion Lance Armstrong and last year's runner-up Alex Zulle will need good legs, the support of team-mates and a strong nerve as they battle over the major climbs.

Miguel Indurain: Even the best suffer at Hautacam

The climb to the top of the Aubisque lasts almost 20km. The 30km descent is punctuated by a short, sharp climb over the Soulor, before the final gruelling ascent to Lourdes Hautacam.

After 190km of racing, the riders will be asked to ascend 1000 metres in altitude over just 15km.

This steep climb was not used before 1994, but has seen thrilling racing on its previous appearances during the Tour - whatever the weather.

In 1994 the stage featured a foggy climb into the clouds won by Frenchman Luc Leblanc.

Riders will be hoping for weather closer to this 1996 ascent, when the Dane Bjarne Riis confirmed his dominance over five-times winner Miguel Indurain under a hot sun.

Jalabert quickly relinquished the lead last week

This year's stage winner could be a pure climber like Leblanc or, like Riis in his great year, an overall contender for victory.

If a climber breaks free it might be Pantani, Frenchman Richard Virenque or one of the Spanish mountain experts such as Fernando Escartin or Jose Maria Jimenez.

However Ullrich, Armstrong and Zulle have all won mountain stages in the Tour, and any one of this trio could use this first important stage to exert their authority in the race.

BBC Sport Online will be providing regular updates from the mountain stages of this year's Tour. Click here during Monday's stage for details.