The downhill is an alpine skiing discipline. Sir Arnold Lunn originally developed the ru vles for the downhill for the 1921 British National Ski Championships.

The downhill discipline has the greatest risks of all the alpine events because it involves the highest speeds. On a typical international-level course, competitors will reach or exceed speeds of 130 kilometers per hour (80 mph) and some courses, speeds of up to 150 kilometers per hour (93 mph) in certain sections are expected. To be competitive in the downhill, racers must have considerable strength and a high level of technical expertise.

Course

A typical downhill course will begin at or near the top of the mountain on a piste (marked ski run or path). The ski run is closed off to the public and groomed specially for the race. To inhibit dangerous rutting of the course and also to increase speed, usually water or salt are spread throughout the course to make sure that it gets icy. Gates, which are always the same color in downhill, are spaced great distances apart, but not out of sight from each other. In the world's most famous ski areas, the courses are well-established and generally do not change much from year to year.

By design, each course is set up to challenge the best skiers in a variety of ways. The racers must ski at high speeds over ice, through difficult turns, extreme steeps, flats, and huge airs (jumps). For the thrill and excitement of both the racer and the spectators, a good course will have all these elements in it. 

Equipment

Skis used in downhill are much longer than those used in lower-speed alpine events. The longer skis provide added stability at high speeds and often have rounded, low-profile tips rather than pointed tips. Ski poles are bent so that they curve around the body when the racer is in the "tuck position" and sometimes have aerodynamic, cone-shaped baskets. Downhill racers wear skin-tight suits to minimize drag, and helmets are required.

During the 2003-2004 season an attempt to increase safety saw the minimum sidecut radius for downhill skis increased to 45 meters (from 40 m) and a minimum ski length was imposed for the first time:

Races

Racers are allowed extensive preparation before the race. The preparation typically includes daily course inspection and discussion with their coaches and teammates as well as several practice runs before the actual race. It is important that the racers do not make any unnecessary turns while on the course, and try to do everything they can to maintain the most aerodynamic position while negotiating turns and jumps.

The downhill race is a single run. Times typically fall between 1 minute, 30 seconds and 2 minutes, 30 seconds for Olympic courses and must be over 1 minute in length to meet international minimum standards. Tenths and hundredths or thousands of seconds count. Olympic races have sometimes been decided by as little as one or two one-hundreths of a second, and ties are not unheard of.

Risks

Downhill is a high-risk sport as it is possible for racers to suffer serious injury or even death while practicing or competing. The ski racing community is very aware of the inherent risks in downhill skiing. As a precaution, safety netting and padding are placed in worrisome areas where race officials anticipate crashes.