Serious skiers concentrate primarily on their performance on the slopes, but apre s-ski evenings often are the setting for lively discussions of -- and arguments over -- statistics on the sport. The following facts about U.S. resorts -- although some ski authorities may disagree -- are based in part on data compiled by Robert G. Enzel for "The White Book of Ski Areas."

*Highest lift: Keystone/Arapahoe Basin, Colo. (12,450 feet) -- with Loveland Basin, Colo., (12,430 feet) a very close second.

*Longest ride on a North American lift: Gondola at Killington, Vt. (3 1/2 miles, 28 minutes).

*Steepest officially marked trail: At Squaw Valley, Calif., where the west face of "KT22 Chair" drops more than 1,700 feet vertically with an average pitch of well over 35 degrees.

*Longest official trail: Killington's "Juggernaut" beginner run (54,695 feet).

*Most difficult trail: Peregrine at Beaver Creek, Colo.

*Resort with the most vertical drop: Jackson Hole, Wyo. (4,139 feet).

*Resort with the largest lift capacity: Mammoth Mountain, Calif. (35,000 skiers per hour).

Resort with the most natural snow: Alta, Utah (about 810 inches last year -- yearly average runs around 500 inches).

*Resorts with the longest unbroken seasons last year: In the east -- Killington (Oct. 20 to June 21); west -- Mount Bachelor, Ore. (Nov. 18-July 29). Timberline, also on a glaciated Oregon mountain, has split seasons (Nov. 9-April 30 and June 15-Sept. 10 last year).

*Highest priced lift ticket at a major resort: Deer Valley, Utah ($28 a day, $18 a half day); lowest priced: Alta ($12 a day, $9 a half day).

*State with the most ski areas: New York (63 downhill ski centers and 186 cross-country).