Flying is the fastest way to cover distance in the Red Bull X-Alps. But flying a paraglider depends on rising air in thermals to take the athletes up high. Thermals develop when the sun heats the surface and bubbles of hot air rise just like in a boiling pot of water. 

The last days however, there hasn't been a lot of sun. Luckily, there is another way for paragliders to stay in the air and make good distance. It's where they soar on the winds that blow upslope.

If wind blows against a mountain or hillside, it is forced to go up because it can't go anywhere else. Birds and paragliders alike can use these dynamic upslope winds to stay in the air. 

If the winds are constant, athletes can soar for kilometers on end, as long as they stay relatively close to a slope. In that way, they can cover 35 to 40km per hour, instead of just 5 to 10 on foot. 

Having a very light paraglider wing actually help this soaring. A light wing is generally easier to launch in light winds and will surf on the light upslope winds easier than heavier wings.

The wings are so light, generally less than 3kg, because the fabric they are made of gets lighter every year. The extremely light paraglider fabric that Porcher developed for this year's paragliders not only helps the athletes hike further with a lighter backpack, but also to soar better when the sun doesn't shine.

Check out where the athletes are soaring on Live Tracking.