Rivers swollen with melted snow lure rafters and kayakers from spring through midsummer, when rivers are at their fullest. Salida has become a famous rafting center; other popular destinations include Fort Collins, Estes Park, Grand Junction, and Glenwood Springs.

Rivers are classified from I to VI, depending on the roughness of their rapids. Class I is an easy float trip, practically calm; class II has some rapids alternating with calm; class III has some difficult rapids, with waves and boulders, and can be narrow in spots; class IV is considered very difficult, with long stretches of rough, raft-flipping rapids; class V is extremely difficult with violent rapids and steep drops; and class VI is considered unrunnable The Arkansas River near Salida offers a variety from easy to almost unrunnable, and the Colorado River through Glenwood Canyon is a particularly scenic class II to III river, wild enough for some thrills but with enough calm stretches to let you catch your breath and enjoy the view.

You'll find a variety of trips from numerous reliable outfitters. For a free directory of licensed river outfitters and tips on choosing a rafting company, contact the Colorado River Outfitters Association, P.O. Box 1662, Buena Vista, CO 81211 (tel. 303/280-2554; www.croa.org).