Stacks Image 471

Moffitt Butte - Remnant of a Hydrovolcano

Of all the buttes in Central Oregon, only a few are hydrovolcanoes, where rising magma intermixed explosively with surface water (such as a lake or underground aquifer) to form a layered ring of solidified volcanic rock known as tuff. One of the more accessible but less-visited of these picturesque tuff rings is Moffitt Butte, just a 50-minute drive south from Bend, off of Hwy 31. Here a 2.6-mile (roundtrip) closed road hike leads up into the tuff ring with long sweeping views, plus cross-county treks to dramatic tuff formations around the rim.

Origins of the Moffitt Butte Tuff Ring
Unlike most volcanic eruptions in Central Oregon, which were typically dry and left rounded cones of cinders and ash, the eruption at Moffitt Butte began about 75,000 years ago deep underground with the mixing of magma and groundwater that was
Graphic of tuff ring development
greatly compressed by the overlying rock. Once this mixture of steam, magma, water and broken rock finally reached the surface, it erupted violently. However, since this material was relatively sticky and had the consistency of a mudflow — once the steam was released — it deposited in a broad low ring around the vent (see diagram at left).

As the eruption continued, surge after surge of these sticky, expanding rings of thick, wet ash and rock fragments built up around the vent, leaving layer upon layer of concrete-like slurries that eventually cooled and hardened into the yellowish tuff rock found today. At Moffitt Butte, these tuff layers built up a ring that rises over 400’ above the surrounding terrain. At the end of the eruption, after the connection of magma to the ground water was sealed off, a subsequent rise of lava filled the interior of the tuff ring with a pool of basalt that cooled into today’s relatively flat caldera floor (see cross-section below).

Stacks Image 479

Hiking the Moffitt Butte Tuff Ring
The start of the Moffitt Butte hike, off of Highway 31 south of La Pine, is easily accessible by any passenger car in almost any season, outside periods of winter snow accumulation (see Road Map download below). However, there is not a lot of shade on this high desert hike, so the cooler days of spring and fall are likely the best.

View of road hike up into the caldera
From the informal parking area, the hike goes north on a dirt road for 80 yards to a “T” where one turns right (east). The route then follows this relatively flat dirt road for 0.4 miles, through a young ponderosa pine plantation, to a “Y” where one bears left (north). The route then follows this dirt road north for 0.6 miles, climbing up about 300’ onto the flat floor of the caldera (see Trail Map download below).

Once up on the caldera floor, just where the road bends to the west, one can hike cross-country about 300 yards east through an old burn area to the East Rim of the tuff ring, where there are wide views over the caldera floor and the mountain ranges to the south. Returning to the dirt road, the route continues northwest for another 0.3 miles to the road’s end on the West Rim of the tuff ring. Here one has spectacular, sweeping views over dramatic tuff outcrops to the High Cascades on the western skyline. One hike option is then to turn around here and retrace the route back along the dirt road to the parking area.

Tuff formations on the south rim
A more rugged option for further views and fascinating tuff formations is a cross-country loop hike for 0.7 miles around the west and south rims and back to the road. There is no trail here, but one can follow game trails through the open forest just behind the rim of the tuff ring. From the West Rim viewpoint, this route goes south 0.4 miles along the west rim, climbing up about 100’ to the South Rim. The hike then goes 0.3 miles east, staying high up behind the south rim (with close up views of the tilted, layered tuff deposits), before descending back to the road in the old burn area.

The hike along the road to the West Rim and back is 2.6 miles roundtrip, with an elevation gain of 350’. Adding in the cross-country trek to the East Rim is a 3.0-mile roundtrip hike. The full loop hike to the East, West and South Rims is 3.5 miles roundtrip, with a 475’ elevation gain.

Download (PDF, 868 KB): Photos of Moffitt Butte Hike
Download (PDF, 768 KB): Road Map for Moffitt Butte Hike
Download (PDF, 776 KB): Trail Map for Moffitt Butte Hike

DISCLAIMER: Every effort has been made to ensure the accuracy of this information, but the authors do not guarantee that it is either current or correct. The reader assumes full responsibility for any use of this information, and is encouraged to exercise all due caution while recreating.

Back to Blog Page