A look at how warmer weather affects athletes in various outdoor sports at the Winter Olympics:
ALPINE SKIING: Cold keeps the snow along the course icier and therefore more compact and slick. Warm temperatures can melt and soften the snow, which changes the way a skier approaches a run, and sometimes which particular skis they decide to use. During a race, softer snow means it's easier to make turns, but it also slows skiers down, so they can take more risks and be more aggressive — and they need to attack more, because otherwise they won't generate the necessary speed, particularly in an event such as the downhill, which the women race Wednesday.
HALFPIPE: There's a phrase riders use when the temperature soars and the condition of the halfpipe wanes: mashed potatoes. That mush slows riders down, making it harder to get enough air to pull off all the flips and twists required to wow the crowd. It's sort of like the difference between backing your car out of your driveway with 3 inches of fresh snow on the ground, then trying the same thing in slush; the car slides through hard-packed snow, but sinks in the goopy stuff. As the temperature climbs toward freezing or above, the halfpipe gets slower.
SLOPESTYLE: The firmer the snow surface, the better it is for slopestyle skiers and snowboarders, because it gives the athletes a truer takeoff point, and as in halfpipe, less speed means less air for tricks.
SNOWBOARDCROSS: The athletes in snowboarding's version of NASCAR aren't quite as finicky as their halfpipe and slopestyle counterparts. Racing down a mountain several times a day under constantly changing conditions makes riders make quick adjustments, particularly with what kind of wax is on their board. It can be overcast and below freezing in the morning, then sunny and balmy in the afternoon. Soft snow can slow things down considerably and turn races into more as much about strategy as speed. Alex Deibold of the U.S. brought eight boards to Sochi, double his usual number, so he and the team wax technician can find the right setup.
SKI JUMPING: When the artificial snow in the landing area for the jump hill softens under the sun, there are injury risks for the athletes. Landing becomes bumpy, which can throw competitors off-balance and make them fall. Also, their skis could dig too far into the snow. The ramp itself is unaffected by temperatures, because it's kept cool by a refrigeration unit.
CROSS COUNTRY AND BIATHLON: With soft snow, courses become treacherous in the downhill curves, where it's easy to lose one's balance at high speed on thin skis. Changing conditions also make things harder on the wax technicians, who prep the skis before each race to suit the snow temperatures. Different wax setups are used for warm and cold weather to give the skiers the best glide and grip. The teams usually test a number of different setups each day, and getting it wrong can take even the biggest favorite out of contention. In long-distance races, wet snow is also more tiring to ski on, and can benefit the lighter racers. Ola Vigen Hattestad won the men's cross-country freestyle sprint Tuesday after three of his rivals fell in the final.
SLIDING SPORTS: Many of the sliding competitions are being held at night, because when the temperature drops, ice quality improves. Miles and miles of pipe installed in tracks pump temperature-controlled ammonia through the concrete, keeping the surface cold enough during the day, even when the temperature tops 50. Shades installed on the track's roof shield the ice from the sun, and workers spray dry ice and water. Still, colder air means colder ice, and colder ice means faster ice. The longer it stays warm in the mountains, the softer the ice will get, meaning more guesswork for teams about what sort of runners and setups to apply to their sleds.