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Snow/glacier/ice route
Elevation Gain
2,500.00 ft (762.00 m)
8.80 mi (14.16 km)
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Only fully discovered and documented in 2011, Mount Hood's Sandy Glacier is home to the largest and most extensive glacier cave system in the contiguous United States.

The caves begin a mile uphill from McNeil Point, where erosion from the rapidly-retreating glacier on Mount Hood's western face has created a combined 7,000 linear feet of caverns, caves and narrow passages. Known today as the Sandy Glacier Caves, this extensive network is comprised of three main caves: Snow Dragon, which has recently experienced a collapse, Pure Imagination, and Frozen Minotaur.

Though initial cave sightings were reported as early as 2000, their existence was only officially confirmed via a YouTube video by Gregory Fowler in 2010. Based on the video, mountaineers, cavers, and close friends Eddy Cartaya and Brent McGregor enlisted help from friends and several local mountain rescue teams and embarked on a series of painstaking expeditions to fully map and document the that they would later name Snow Dragon. While on the expedition in 2011, they further discovered Pure Imagination and Frozen Minotaur.

The Science

Mount Hood's Sandy Glacier Caves in January of 2014. Photo by Tyson Gillard.

Scientists have documented the recent and widespread retreat of glaciers due to climate change for a number of years. Using surface-scanning technologies such as lidar, scientists can fairly easily track the changing volume of glaciers. Tracking this change from inside the glacier is a new approach, however, and teams like Cartaya and McGregor's and photographers like Eric Guth hope to better understand this interior deterioration and to share this information with the world.

Glaciologists have found that large glacial caves such as these only occur in thin, dying glaciers, whereas caves that form in larger and thicker glaciers quickly collapse under their own weight. Because the peaks of the Cascade Range lie in relatively warm climates (as opposed to Alaska, for instance), surface friction alone is often enough to introduce some melting. Once a channel of water is formed, its size will only increase over time as more water passes through. Additionally, the caves allow warm air to enter deep into the glacier, ensuring an even quicker melting process.

The Sandy Glacier Caves in January of 2015, notice the collapse of Snow Dragon. Photo by Shane Kucera.
The caves seen from McNeil Point in November of 2015. Photo by Andrew Stohner.

The process is not without precedent: The Paradise Glacier Caves on Mount Rainier's south side were once a major attraction to the national park. By the 1970s, however, the ceiling began to collapse. Today, the caves are long gone, and the lower portion of the glacier no longer exists.


Safety + Getting There

From the McNeil Point Shelter, it is a long and exposed off-trail traverse to the cave entrances at roughly 6,500 feet. In late summer, the field of steep talus is only intermittently held together by ground juniper, pink mountain heather, and the occasional mountain hemlock or whitebark pine. The spring and summer seasons are also when the majority of melting occurs and when the caves pose the greatest danger, as large boulders constantly drop from the ceiling and sheets of ice break away from the entrances. SPRING AND SUMMER TRAVEL IS NOT ADVISED.

Relatively speaking, winter is the safest time to be inside the caves, although falling debris is still common. The off-trail traverse from the McNeil Point Shelter is steep and requires crampons and ice axes at the minimum. Adventurers should give themselves at least 7 hours to reach the caves from the Top Spur Trailhead. NF-1828, which leads to the Top Spur Trailhead, is not maintained during the winter months, however. If you are unable to reach the Top Spur Trailhead due to snowpack, you may have to park 7.8 miles further down the road at at Muddy Fork Road.

Logistics + Planning

Preferable season(s)




Parking Pass

NW Forest Pass


Largest known glacier cave system in lower 48 states.


Technical traverse across McNeil Point Ridge. Rock fall inside caves.

Pets allowed

Not Allowed

Trailhead Elevation

4,000.00 ft (1,219.20 m)


Backcountry camping
Big vistas
Old-growth forest

Typically multi-day



Nearby Adventures

Nearby Lodging + Camping

Mt. Hood + Clackamas River Area, Oregon
Mt. Hood + Clackamas River Area, Oregon
Oregon, Mt. Hood + Clackamas River Area


Awesome spot, approached from McNeil via the ridgeline for some mixed rock/ice fun, came back below the ridgeline, which was much easier. Caves were real cool, though a proper exploration was cut short by some incoming clouds. I lucked out with enough snow to cover the scree on the traverse over there, but not enough to make the trailhead (Top Spur) inaccessible.
Amazing adventure on my first time out to the caves! Took a bit of route work for us to get there following good, but in-direct tracks. Snow is melting down rapidly leaving a lot of gaps in the Sandy on the walk up to to the caves.
The snow level is now down to the Top Spur Trailhead, good traction tires and a snow-worthy vehicle are recommended. We decided to extend the adventure to two days to take in some sunset/sunrise views. The temps at the McNeil Point shelter dropped to ~10degrees overnight, but the shelter provided respite from the winds.
As described in other posts, the caves have receded greatly since our last trip in April. The ceiling portal in Pure Imagination no longer exists, but the caves still provide a sense of awe and wonder when exploring.
The traverse was icy and still had exposed rock and grasses at times. We decided to use crampons, which made the trek simpler, but please check snow conditions before making a decision on what gear to use.
No permit is needed at the Top Spur Trailhead at this time.
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