To kick things off, I’m going to start with the twin Hawaiian volcanoes of Mauna Kea, and Mauna Loa. Both are dormant, incredibly huge volcanoes on the Big Island of Hawai`i. Skiing these volcanoes requires a lot of effort, solid planning, and good timing, but they are probably the easiest ones on my list. People ski Mauna Kea frequently, as there is relatively easy access due to the road to the numerous astronomical observatories that dot the summit.


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Skiing Exotic Volcanoes - Mauna Kea and Mauna Loa, Hawaii


Shaded Relief Map of the Hawaiian Islands, from, data from USGS / NASA

I’m going to be switching things up for a while here at “ask Dr. Kaye.” I”ll be putting the science topics on hold for a few weeks, and in their place I’ll be bringing Unofficial Networks a series of articles about backcountry ski touring on my top-ten list of exotic volcanoes.

I’ve been dreaming of climbing and skiing all of these magnificent mountains for years, and along the way I’ve been gathering as much information on them as I can. While I might not be able to hop on a jet and start ticking them off quite yet, maybe someone out there can – and I’d like to help. This series of articles will present location and access info, outline geologic history, discuss possible future eruption hazards, and provide details on how to check in with the local volcanologists before you go. Oh, and of course I’ll share whatever information I have found about who has skied the volcanoes before and what their experiences were like.

These mountains are no joke, so if you decide to hop on a plane and climb and ski them – do your homework and treat them with the utmost respect – they are beautiful but in some cases exceedingly dangerous!

To kick things off, I’m going to start with the twin Hawaiian volcanoes of Mauna Kea, and Mauna Loa. Both are dormant, incredibly huge volcanoes on the Big Island of Hawai`i. Skiing these volcanoes requires a lot of effort, solid planning, and good timing, but they are probably the easiest ones on my list. People ski Mauna Kea frequently, as there is relatively easy access due to the road to the numerous astronomical observatories that dot the summit.

The Big Island of Hawai`i from Space, from Mauna Kea is at top, Mauna Loa to it’s south across the Saddle. 

Both of these Hawaiian volcanoes are exceptional, and both are blanketed by occasionally thick snowfall in winter months. Mauna Kea rises to 13,767 feet above sea level, and is a mere ~130 feet taller than Mauna Loa across the “Saddle” (Pohakuloa to da Kanakas). In Hawaiian, “Mauna Kea” means “white mountain.” Counting its height from the bottom of the sea to the summit, Mauna Kea easily surpasses Mt. Everest in total height by almost 4,500 feet. Not to be underdone, Mauna Loa has such a massive bulk that it easily wins the title of the largest single-source volcano on earth, second only in the solar system to Olympus Mons on Mars. So here you have the tallest mountain on earth right next door to the most massive – and you can potentially ski them both and go surfing later that day.

Geography and Geologic History

Mauna Kea and Mauna Loa have markedly different summit morphologies. Mauna Kea has a steep summit pocked with cinder cones, and there is even a small lake in one of the cone’s craters – lake Waiau. Mauna Loa has a broad, gentle summit, and is mostly flat except for the enormous summit caldera, Mokuaweoweo. The morphology of Mauna Loa is such that the summit cannot be seen from sea level due to the flatness and broad “shoulders” of the volcano.

Mauna Kea

Mauna Kea is thought to have progressed past the “shield building” stage, which is the stage of the volcanic lifecycle still occupied by actively erupting Kilauea volcano, as well as the dormant volcanoes Mauna Loa and Hualalai to it’s South and Southwest, respectively.

Hawaiian shield volcanoes exhibit summit calderas and radial “rift” zones with elongated fractures down their flanks from summit to sea. Once the volcanoes mature beyond shield building, they begin to erupt smaller isolated pockets of magma that is more viscous and comparatively rich in silica than lavas previously erupted. This helps these volcanoes gain steep summit areas. Some of the cinder cones on Mauna Kea have slopes that are at the angle of repose, or >30 degrees. As you can imagine, this makes for delightful skiing when they are coated in snow.

The last eruption from Mauna Kea was 4,000 years ago, at the close of the mountain’s last period of volcanism that extended from 6,000-4,000 years ago and bore forth eight different eruptions. In fact, each eruption in the last 60,000 years has produced a lava flow, so the next one is almost certain to do the same. This flow could be on the order of 9-15 miles from the summit, or could be from any location on the volcano and could potentially reach the ocean.

As recently as 13,000 years ago, Mauna Kea was glaciated. You can see the striations left in the lava rock from the ice as it flowed its way down the mountain, as well as numerous lateral and medial moraines high upon the volcano’s summit. These Hawaiian glaciers have long since retreated as a consequence of cyclical natural climate change. Given the way things are going today, it’s is highly unlikely that they should return any time soon. But it’s intriguing to think about eruptions that may have occurred under the ice cap long ago – and there is evidence for torrential floods that eroded deep canyons on the flanks of the volcano.

Mauna Kea is long thought to be dormant, but scientists wouldn’t rule out the possibility of a late-stage cinder cone eruption on its flanks. Such an eruption would presumably be preceded by ample warning in the form of inflation, gas release, and numerous earthquakes. In terms of volcanic danger today, Mauna Kea is a very safe place to ski, as the hazards are primarily weather and altitude-related and not volcanic in nature.

Mauna Loa

Mauna Loa is an entirely different beast than present-day Mauna Kea, as it is either still in the latter half or right near the end of it’s shield-building stage of volcanism. Mauna Loa is thus capable of awakening and venting forth an eruption from the summit with little warning. Recent advances in instrumentation and a hyper-vigilant and extremely capable staff at the Hawaiian Volcano Observatory mean that any degree of awakening would be noticed and reported. The remoteness of the volcano and the lack of communication abilities at the summit mean that if you are up there and something goes down, you are probably on your own.

Mauna Loa’s summit caldera Mokuaweoweo from the air, with Mauna Kea in the background. Photo by Jack Lockwood – USGS

Mauna Loa last erupted in 1984, and lava flows that spilled out of it’s summit caldera, Mokuaweoweo, almost reached the city of Hilo about 30 miles away.

Lava flows on the flanks of Mauna Loa during the 1984 eruption, from the USGS.

Some of the flows from Mauna Loa have reached the coast, over 20 miles away, in less than a few hours. While Mauna Loa erupts silica-poor, low viscosity magmas which are inherently less explosive and therefore relatively safer than the andesite lavas of the Cascade volcanoes, the mountain is still potentially hazardous, especially if one would happen to be on or near the summit when it woke up. If the volcano shows even the slightest signs of reawakening, it would be wise to steer clear of it and head to the easier target of Mauna Kea instead.


Mauna Kea gets skied quite often, and it snows in Hawai`i a lot more than people think. Sometimes it even snows a few feet at a time up on the tops of the Big Island, and for the adventurous, knee-deep pow is even a possibility.

I got in touch with my good friend and incredibly talented  volcano photographer Brad Lewis. Hey Brad! I can’t believe you’re a professional photographer – I’m so much better than you! Not that that’s out of the way, Brad sent along two of his favorite shots of skiing and snow on Mauna Kea.

Summit cones on Mauna Kea, coated in fresh snow, © G. Brad Lewis /

Skiing on Mauna Kea, © G. Brad Lewis /

For more on Brad’s experiences skiing on Mauna Kea, check issue #2.3 of the Ski Journal, where he wrote a great article called “Lei-ing Down Turns” a few years back, here’s a snippet from the Ski Journal’s site where you can subscribe to read the entire piece:

“It’s been pounding rain for days. I’m hunkered down in my home at 4,000 feet on top of Kilauea volcano, on the island of Hawaii. It’s mid-winter, and the constant rumble of thunder assures me that snow is falling above 10,000 feet. When the sky finally clears, the massive slopes of Mauna Loa are covered with snow. I go outside to my coffee patch and see that Mauna Kea has even more white gold. The radio reports that six-foot snow drifts are blocking the Mauna Kea summit road, but I gear up and bolt for it anyway, knowing how sweet the first tracks will be when it finally opens. After all, I’m in the middle of the Pacific among surfers, pineapple growers, and cattle ranchers—who minds waiting for powder?” – G. Brad Lewis.

Mauna Loa offers the potential for some serious lines along the walls of the Mokuaweoweo caldera. The caldera is approximately 4 miles in length and 1.5 miles across,  and its walls reach upwards of 600 feet in height on the SW rim, which has a snow-saving NE aspect.

The NE-facing rim of Mokuaweoweo Caldera, from

Plaster that in some high water content snow and you could have yourself some incredible steep skiing. Although I have only camped up there in the summer months, I have hear rumors of snow having fallen down to 10,000 feet, and in depth of up to 2-3 + feet. Suddenly, in addition to the prospect of 600’ of Tram Face-like steep skiing, you have 3,000’ of vertical? In Hawai`i??? As enticing as that might sound, the remoteness and ruggedness of the terrain makes it a virtual impossibility. Maybe once every 50 years there would be enough snow to pull off a descent down the flanks of the volcano.

Access Beta

Mauna Kea is an easy target, although only a few rental car companies will let you drive their vehicles on the Saddle road. The summit access road is paved almost the entire way, in an effort to keep dust down for the numerous astronomical observatories that dot the summit cone.

From Hilo: Take the “saddle Road” a.k.a. Hawai`i State Highway #200 west for about 21 miles. Be extremely careful as you drive this highway, because it is barely wider than one lane in many places, and has numerous winds, twists, and blind corners. The locals also tend to drive the road right down the middle of the highway, straddling the double yellow line to avoid the edges where years and years of patching will make your ride bone-jarring and teeth-rattling. Hence it’s called the “Straddle Road” by many.  Make a right on to the Mauna Kea Access road, and drive up to the visitors center and get out and stretch your legs and acclimatize. You are now at 9,200 feet, and you were at sea level about 45 minutes ago so your body may not be that happy with you. Also, if it’s been snowing heavily, there’s a good chance the road may be closed at this point, which means you have a long, long way to skin to get to the summit.

From Kona: Head north towards Kohala and Waikoloa on the Mamalahoa Highway, a.k.a. the Hawai`i Belt Road. Thus road undulates like a roller coaster, and the same scenario as that mentioned above with the “Straddle Road” from the Hilo side applies here. You’re in Hawai`i – take it slow and easy!  Make a right onto the Saddle Road after about 48 miles. Then take a left onto the Mauna Kea access road after 14 miles on the Saddle Road. You will transit the Pohakuloa Military Training area so beware of live-fire exercises.

Getting yourself to the top of Mauna Los is another story. There are basically two options – drive up to the saddle and then to the NOAA weather observatory and hike from there, or start hiking from the Hawaii Volcanoes National Park on the East side.

If you choose the Saddle approach, the farthest you will get on a paved road is the NOAA observatory at an elevation of ~11,000 feet. By “paved” I mean someone put some asphalt on it with a few shovels here and there over the last 25 years. The white line painted on the road is there for you to follow in frequent fog, so be sure to go extra slow driving up there. Incidentally, the Mauna Loa weather observatory is the site of some of the measurements of global CO2 that underpin the current theories of global warming were collected since the 1950s by Charles Keeling (see this fascinating article here at the NY Times).

If you try to make the hike with ski gear, you will certainly suffer a degree of suffering few humans know. The trail starts at the Mauna Loa strip road, takes at least a few days, is 38 miles long over some of the most unforgiving sharp fields of lava, and gains over 7,000 feet. The late Shane McConkey once hiked it in the summer without ski gear and I recall him telling me it was one of the most taxing things he ever did. Unless you are Chris Davenport, I would try to drive up the Saddle and hike from there.

Where to Check in with the Local Scientists

Before you head to the Big Island, be sure to check the latest information on Mauna Kea and especially Mauna Loa. The Hawaiian Volcano Observatory is the source for all volcanic information on the Big Island. Here are links to the updates from each volcano:

Mauna Loa and Mauna Kea:

If you’re looking for Kilauea updates check this link:

Coming up in the following weeks:

Mt. Erebus, Antarctica
Yotei Volcano, Japan
Kluchevskoy Volcano, Kamchatka
Cleveland Volcano, Aleutian Islands, Alaska
Mt. Ngaruhoe, Aotearoa, New Zealand
and more!



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