★★★★☆ Easy / Flagstaff Area
Headlamps required – on this naturally refrigerated hike through a short underground tunnel. Thrill seekers will love turning off their lights for a second to experience total darkness. And bonus… the Lava River Tube’s year-round 40° temperature makes this hike a definite “Yes” when the thermometer rises.
TRAILHEAD: Forest road 171B, north of Flagstaff • DIFFICULTY: easy (Moderate at start) • DISTANCE: 1 MILE (2 MILES RT) • APPROX. TIME: 1-1.5 HOURS RT • ELEVATION GAIN: -minimal • APPROX. CALORIES BURNED: 260-300 • BEST TIME OF YEAR: March-OCTOBER • PETS: YES (but not recommended) • KID FRIENDLY: very • FACILITIES: NO • FEES: NONE
Grab a headlamp, a light jacket and some gloves before setting out on this quirky family-friendly hike. Standing before the wide opening to the Lava River Tube (basically a long underground cave), a cool breeze hints at the interior’s constant 35-45° temperature.
For the first quarter-mile, a cascade of stones slants downwards This is the only steep section of the Lava River Tube Hiking Trail. Afterwards, the cave levels out and continues evenly to its end, less than a mile further on.
The inside of the Lava River Tube is mostly wide and tall, with enough standing room for even Shaquille O’Neil. Only one brief 4-foot high section requires a slight stoop to pass through. The tube is easy to follow, with a bumpy stone surface that makes thick-soled shoes a plus. Leave the flip-flops at home for this hike.
At the tube’s end, switch off the lights, if you dare! The velvety darkness is so complete that objects just inches from your nose are impossible to see. For this reason, it’s smart hike with fully charged batteries – ya’ know!
The Lava River Tube was formed about 700,000 years ago, when molten lava oozed from a vent in the earth. As the lava flowed forward, in an underground “river,” the outer edges cooled and solidified, while the hot center continued to flow out. The result? A hollow tube perfect for a cool family hike.
Directions From the intersection of Humphries Street and US 180 (in Flagstaff) take US 180 for nine miles to FR 245 (at milepost 230). Turn left / west on FR 245 and continue three miles to FR171. Head left / south and drive one mile to FR 171B. Turn left here, at the signs for Lava River Cave. The trail head parking lot is a short distance further on. Note: Forest Roads are often closed during winter snow, making this hike inaccessible.