LAVA BEDS, CA
Descend into an Ice Cave
December temperatures can swing into the high 60s at Lava Beds National Monument. But 100 feet below the cinder-covered surface, in the Crystal Ice Cave, it’s below 32°F year-round–prime conditions for ornate ice formations. You’ll need a helmet, headlamp, gloves, and kneepads for this four-hour, quarter-mile scoot-and-shimmy past enormous ice columns, rounded stalactites, and an awe-inspiring 20-foot-tall crystal curtain. Afterward, pitch a tent at the lava-covered Indian Well campground north of the visitor center. The next day, squeeze in trips to three other frozen caves: Skull, Heppe, and Merrill (the latter once housed a skating rink). Make reservations three weeks in advance. (530) 667-8113; nps.gov/labe
Soak in the steamy waters of Stewart Mineral Springs. (530) 938-2222; stewartmineralsprings.com
From Redding, drive 70 miles north on I-5 to US 97. Drive 54 miles north to CA 161. Turn right, drive 17 miles to Hill Road, and turn right again; follow signs for the monument’s visitor center.