Approximately 133 miles of designated motorized snow trails are concentrated around the Lemolo and Diamond Lakes area. The trails are usually open in late November, when snow accumulation permits. Many of these trails are groomed on a regular basis, and all are clearly marked by orange trail signs and diamond-shaped trail blazes pegged up on trees above the snowline.

Contact Umpqua National Forest (Diamond Lake Ranger District, HC 60, P.O. Box 101, Idleyld Park, OR 97447, 541/498-2531) for maps and additional information.

One of the more exotic runs is into Crater Lake National Park. Snowmobiles and all-terrain vehicles (ATVs) must register at the north entrance of the park and stay on the trail. The trail climbs about 10 miles from the park gates to the north rim of the lake.

Be aware that the mountain weather here can change suddenly, creating dangerous subzero temperatures and whiteout conditions. Also, watch for Nordic skiers and other people sometimes found on motorized-vehicle trails.

Diamond Lake Lodge offers both guided snowmobile tours ($150 to Crater Lake, among others) and snowmobile rentals ($100 for 4 hours).