Lava Trail System (Hell's Half Acre)
Upper Snake Field Office 1405 Hollipark Drive Idaho Falls, ID 83401
Lava Trail System (Hell's Half Acre)
Hawaiian Landscape in Idaho
The Lava Trails traverse the desert of the Snake River Plain through contorted landscapes created from multiple lava flows. These Hawaiian-type lava flows are associated with the stretching of the earth’s crust. Hell’s Half Acre lava flow erupted about 4,100 years ago and is 222 square miles or 162,000 acres. The lava flowed at 2,000 degrees Fahrenheit, had the consistency of molasses, and traveled at speeds up to 30 mph.
Geology
Lava rock is extremely sharp, glassy and fragmented, with open cracks, lava tubes and caves. A'a (ah-ah) and pahoehoe (pa-hoy-hoy) lava flows are the most prevalent here. Areas of soil and vegetation not covered by lava are called kipuka, a Hawaiian word meaning 'window in the lava.'
Botany
In the spring and early summer, numerous wildflowers, such as Evening Primrose, Indian Paintbrush, wild onions, penstemon, geraniums, and Prickly Pear Cactus, color the landscape. Bright, green ferns grow in deep cracks. Plants ranging in size from tiny mosses and lichens to juniper trees hundreds of years old grow here. Other native species include sagebrush, rabbitbrush, bitterbrush, blue bunch wheatgrass, and needle-andthread grass.
Wildlife
Wildlife roaming the lava flows include mule deer, antelope, rabbits, bobcats, coyotes, foxes, and rattlesnakes. Soaring above the flows are red-tailed hawks, prairie falcons, and golden eagles.
The Lava Trail system is open to non-motorized recreation activities only.