Hell's Half Acre - Interstate 15, Idaho
Posted by: Groundspeak Premium Member oiseau_ca
N 43° 18.167 W 112° 16.137
12T E 397078 N 4795220
Hell's Half Acre Lava Field is a basaltic lava plain located on the Snake River Plain of Idaho, United States.
Waymark Code: WMPPWW
Location: Idaho, United States
Date Posted: 10/04/2015
Published By:Groundspeak Premium Member lumbricus
Views: 7

According to Wikipedia, "Hell's Half Acre Lava Field is a basaltic lava plain located on the Snake River Plain of Idaho in the United States. It is the easternmost of the basaltic lava fields on the Snake River Plain, located about 25 miles (40 km) west of Idaho Falls, Idaho and 30 miles (48 km) north of Pocatello, Idaho. In 1976, the National Park Service designated the northwestern portion of the site a National Natural Landmark. In 1986, the Bureau of Land Management recommended that 68,760 acres (27,830 ha) of the site, located just southeast of the National Natural Landmark, to be a wilderness study area.

The Hell's Half Acre lava plain is located in Bingham and Bonneville counties in the state of Idaho. The site is about 150 square miles (390 km2) in size. The area where a former lava lake existed is marked by a 875-yard (800 m) long by 328-yard (300 m) wide depression near the summit of the lava field. Ten circular pits and two large lava tubes are also located near the summit.[1] Two major lava flows, each about 6.2 miles (10.0 km) long by 3.1 miles (5.0 km) wide, extend from the main lava field to the south and southwest. These two lava flows surround "Morgans Pasture," a kipuka (or older geologic feature which was not covered by lava). More recently, scientists studying aerial photographs of the site discovered a 328-yard (300 m) long eruptive fissure partly buried under lava flows just 437 yards (400 m) from the northwest boundary of the lava field. This and other features of the site indicate that the fissure vent itself may be 11.8 miles (19.0 km) long.

The site is fairly accessible. Interstate 15 just crosses the southeast corner of the lava field. Two trails have been marked by U.S. Bureau of Land Management personnel. The shorter 0.5-mile (0.80 km) long trail is marked by blue flags, and takes about 30 minutes to walk. The longer, 4.5-mile (7.2 km) long trail is marked by red flags, and takes a full day to walk. The latter trail leads to the central vent. A short trail (about 0.75 miles (1.21 km) in length) with educational signage along the way may be accessed from the north parking lot near the Hell's Half Acre rest area on I-15. A second trail (about 1 mile (1.6 km) in length) with educational signage may be accessed from the south parking lot. This longer trail has a gazebo and scenic overlook at about the midpoint.There is also a 0.25-mile (0.40 km) long handicapped-accessible paved loop with educational signage as well. All trails are closed in winter.Over 100,000 people used the trails in 2007.

The Hell's Half Acre lava plain is home to a variety of plant species. Among them are bitterbrush, bluebunch wheatgrass, foothills death camas, evening primrose, ferns, geraniums, gray rabbitbrush, Indian paintbrush, needle-and-thread grass, penstemon, prickly pear cactus, sagebrush, Utah juniper, and wild onion. Wildlife is also abundant. Species commonly found here include bobcats, coyotes, golden eagles, mule deer, prairie falcons, pronghorn, red foxes, red-tailed hawks, and sage grouse".

Geologists estimate that the Hell's Acre Lava Field was created about 3250 BC. The lava field was created by the Lava Ridge-Hell's Half Acre fissure vent, and marks the southern edge of this area of volcanic activity. This fissure vent was created when one or more magmatic dikes (sheets or tubes of magma cutting across the existing geologic features) found their way to the surface. At the northwestern edge of the lava field is a basaltic volcano, with the fissure vent extending toward the southeast and the Hell's Half Acre site. The basaltic volcano is a shield type. Pit craters and spatter cones follow this active fissure line. Two non-erupting fissures extend northwest from the shield volcano for about 2.7 miles (4.3 km). One scientific team hypothesized that the seven lava fields in the vicinity of Hell's Half Acre may belong to as few as two fissure vents".

Source: Wikipedia
Waymark is confirmed to be publicly accessible: yes

Access fee (In local currency): .00

Requires a high clearance vehicle to visit.: no

Requires 4x4 vehicle to visit.: no

Public Transport available: no

Website reference: [Web Link]

Parking Coordinates: Not Listed

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