Trail crosses rare maar in northern Arizona

Rattlesnake Crater

Day hikers can walk through a rare volcanic crater known as a maar in Arizona’s Coconino National Forest.

The 1.5-miles round trip Rattlesnake Crater Trail is more of a walkabout than a designated path. The crater is part of Arizona’s massive San Francisco Volcanic Field.

Sprawling across 1.856 million acres, Coconino National Forest is largely centered on Flagstaff. It’s popular with multiple hiking trails, especially north of Flagstaff where it sits between the city and the Grand Canyon. Rattlesnake Canyon marks the national forest’s most interesting feature closest to Petrified Forest National Park.

To reach the trailhead, in Winona, Ariz., from Interstate 40, exit north onto Townsend-Winona Road. Turn left/east onto Angell Road/Coconino County Hwy. 394. The beat-up road parallels the freeway. Next, go left/northeast onto Porter Ranch Road, a dirt road. Go left/north onto County Hwy. 504 then right/southeast onto County Hwy. 785. At a Y in the road, go left/northeast so that you stay on Hwy. 785 (Don't go straight/south onto Hwy. 9127T). When the road dips at about about 0.75 miles from the Hwy. 9127T junction, pull off to the side of the road and park.

Down a volcanic crater
The trail is the dirt road. You'll walk into the shallow crater that is rounded by two short hills. The older, crescent-shaped northern hill is shorter than the southern one.

A maar is a crater formed when rising magma heats the groundwater above it, resulting in explosive blasts of steam. Ejecta from several blasts over time created the two hills.

While volcanic rock and ash can be found on both hillsides, the pinyon and juniper growing there are far more noticeable.

The San Francisco Volcanic Field covers 1800 square miles of northern Arizona. Remnants of more than 600 volcanoes can be found in the field, all formed during the past 6 million years.

When the road ascends out of the crater at a narrow point between the two hills, head back the way you came. While the road continues east, you would just be walking across open desert.

Up a cinder cone
On the walk back, look to the northwest. The San Francisco stratovolcano – topping out at 12,633 feet, is in the far distance. The mountain’s volcanic cone was formed during multiple eruptions between 400,000 and 900,000 years ago. Before the mountain collapsed, the summit reached more than 16,000 feet above sea level. The top 3,500 feet of the mountain flowed eastward as a debris avalanche toward Sunset Crater. Today, the stratovolcano stands as Arizona’s highest point.

You can walk off the road and do a little bushwhacking. One great spot to climb to is the hill on the crater's south side. This hill actually is a cinder (or scoria) cone, essentially a steep conical hill of loose pyroclastic fragments that rose around the vent. Among the fragments are volcanic clinkers and volcanic ash.

If you head up the southern hill’s steep east side and then down its west side, you’ll have a great view of the crater and arrive right back at your vehicle. This route comes to about 1.6 miles or a tenth of a mile longer than sticking to the road that heads through the crater.

The entire hike is unshaded, so be sure to don sunscreen, sunglasses and sunhat. Bring plenty of water as well.

AERIAL MAP

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Hike heads along Arizona meteor crater rim

The Barringer Meteor Crater formed some 50,000 years ago when
a meteorite slammed into northern Arizona. 

Day hikers can walk along the rim of a crater created some 50,000 years ago when a

meteor slammed into what is now northern Arizona.

The 2-mile round trip

hike along the southern rim of Barringer Crater sits in Meteor Crater Natural Landmark.

While privately owned, unlike most tourist traps, this stop is well worth paying the admission fee – there’s literally no other meteor crater as good as this one in the world.

To reach the trailhead, from Winslow, Arizona, drive Interstate 40 west. At Exit 233, take Meteor Crater Road south. The road ends at the visitor center.

10 megatons TNT
From there, guided tours are offered. The main trail heads west along the uplifted crater rim.

The crater is an impressive sight. About 3900 feet in diameter, the crater is 56 stories deep with the rim rising nearly 15 stories above the surrounding desert plain.

Some 50,000 years ago, this region was an open grassland that mammoths roamed with scattered woodlands inhabited by giant ground sloths.

Then one day a nickel-iron meteorite about 160 feet across and traveling at 29,000 mph smashed into the earth here, excavating the crater. The explosion – equal to about 10 megatons TNT or 667 atomic bombs like those dropped on Hiroshima – could be heard across much of North America.

Vaporized
Rock shot up from the impact can be found miles around the crater. As driving in from the freeway to the visitor center, you probably noticed the number of boulders in the surrounding desert growing increasingly more numerous.

About half of the meteorite vaporized while descending through the atmosphere with almost all of the remaining bulk vaporizing upon impact. There are few remains of the meteor, though one box-sized chunk of it is displayed at the visitor center.

Erosion is filling in the crater. The rim crest has lost about 50-65 feet of height since the impact while some 100 feet of lake sediments and alluvium have filled the crater floor. Fortunately for science, the crater sits in the dry Arizona desert, where erosion usually is slow.

Mining engineer and businessman Daniel M. Barringer in 1903 proposed that the crater might be mined for the iron remains of the meteor. His mining company staked a claim and received a land grant, but very little iron ever was found. The crater since has been named for him.

Additional short walks
In addition to the rim hike, you can take a short 0.6-mile round trip trail along the rim to the Moon Mountain Telescope east of the visitor center.

Another 0.3-mile round trip trail takes you slightly down the crater’s side to a view platform and ramada.

The Discovery Center offers a number of interesting exhibits about the crater. An Apollo test capsule from America’s moon race days also is on display.

There’s no natural shade on the hike, so be sure to don sunscreen, sunglasses and sunhat.

TOPO MAP

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