The 1960s were the golden years of the ski boom. New skis, new fashions, new resorts and new skiers mushroomed. But every action has a reaction, and there's a revolution going on in skiing: the meteoric rise of ski touring - cross-country, if you wish.

Ten years ago 15,000 pairs of touring skis were imported. The annual figure is now approaching half a million. Part of that growth is due to the inevitable bottom line of the overwhelming success of Alphine skiing - the high cost of lift tickets, clothes, ever-changing equipment, not to mention the length of the lines at the lifts.

But cross-country skiing has virtues of its own. Its peacefulness, compatibility with the environment and sense of solitude seem more in tune with the '70s than the '60s. Hal Higdon's book, "Fitness After Forty," gives a four-star rating to ski touring as a "total fitness" sport. Downhill skiing gets only a one-star rating because its exercise is intermittent, not of the whole body and not as aerobic. Ski touring is coming late to the Washington area, just as the boom in Alpine skiing came here late.

"Everyone thinks that because Alpin skiingin this area is dependent on machine-made show, cross-country skiing must be next to impossible because of its reliance on Mother Nature," said Terry McCarthy, a local cross-country buff. "But, that's mostly myth." Natural snow cover is frequent in the mountains of Virginia, West Virginia, Maryland and Pennsylvania. McCarthy also pointed out that ski slopes require much more snow because of the pounding they receive from large crowds. "Cross-country trails are fine with three to five inches and hold their snow because they are usually tree-lined and less exposed."

The best trails in Maryland are unplowed forest roads, logging trails and firebreaks in Garrett County's New Germany State Park (phone 301/895-5453) and Savage River State Forest. Farther west try 10 miles of trails in Herrington Manor State Park (301/334-9180) and Swallow Falls State Park (301/334-2038).

In Pennsylvania the most complete program is available at Hidden Valley ski area near Somerset. Rentals, moonlight tours, waxing clinics, 35 miles of trails and noncompetitive "citizen races" are offered. Blue Knob, Seven Springs and Camelback ski areas also have cross-country trails.

Ski touring in West Virginia is centered around Snowshoe resort (304/799-6600) near Slatyfork, Canaan Valley State Park (304/886-4121) and Blackwater Falls State Park (304/259-3216) near Davis. In Virginia, Mount Rogers is the focal point for 20 miles of trails in the Jefferson National Forest.

Recorded cross-country snow forecasts and recommendation services for Virginia, West Virginia, Maryland and southern Pennsylvania are available from Appalachian Outfitters in Reston (703/281-5396) after 9:30 p.m. on Thursday, Friday and Saturday and from Hudson Bay Outfitters (301-840-0664) in Kensington. Both shops offer clinics and trips through the winter, and Outdoor Women (contact Sany Sklar at 942-8677) has scheduled a beginner's clinic for Jan. 30 and two trips in February.