Global Hawaii

Humuula Saddle—Between Giants

Overview

Nestled between the Big Island's two tallest volcanoes, Mauna Loa and Mauna Kea, the sparsely populated Humu'ula Saddle offers an excellent platform for the exploration of both. Hwy 200, otherwise known as the Saddle Road, connects windward Hilo to the leeward Kona and Kohala districts, cresting at 6,500' near the Mauna Kea Recreation Area.

Most of the locals tried to discourage me from driving the Saddle Road. Bad road, they warned, not safe. Indeed the accident rate in the Saddle is higher than along other Big Island routes, so you'll need to drive with extra care and an eye on the weather. If you break down, run out of gas or hit dense fog, you could be stranded for quite a while, and you'd probably end up paying for road service out of pocket. But the route's no more challenging than any other curvy mountain road, and the visual rewards are well worth the ride all along the way.

Things to see here include

The international astronomical observatory complex at Mauna Kea's summit, home to the world's largest telescopes. For lots of great Mauna Kea links, click here.
Mauna Loa's north flank
The NOAA's Mauna Loa Observatory for atmospheric study at 11,000' on the northwest flank of Mauna Loa, accessible by the Mauna Loa Road off the Saddle Road
Colorful roadside Mauna Kea cinder cones
A very early and remote Mauna Loa spatter rampart at roadside
Recent flows from Mauna Loa's northeast rift zone (NERZ)
Several educational astronomical programs offered almost daily by the Onizuka Center for International Astronomy Visitor Information Station at 9,300' on Mauna Kea road. Call (808) 961-2180 for details.

Tips

Take stock of weather conditions at the elevations you intend to visit before venturing into the Saddle. In January, 1999, I was blessed with crystal clear skies, but dense clouds extended from 6,700' to the summits of both Mauna Kea and Mauna Loa on my June, 2000 return; a little lower ceiling would have made the Saddle Road drive interesting indeed. For a last-minute check of conditions at the Mauna Kea summit, pull into the Onizuka Center for International Astronomy Visitor Information Station at 9,300' on the Mauna Kea Road to view the summit cam image updated every 5 minutes. You can reach the center by phone at (808) 961-2180.
Bring a 4-wheel drive vehicle. The steep unpaved Mauna Kea summit road requires 4WD past the residential complex at the 9000' ft level, and it won't hurt on the rugged Mauna Loa Road. Check with your rental agency, however—they may impose prohibitive restrictions on taking their vehicles into the Saddle, and they'll certainly try to discourage you.
Bring binoculars, or any other viewing aid you can get your hands on. The views from on high at Mauna Kea and Mauna Loa are spectacular but distant.
Bring industrial-strength sunscreen. You can feel the intense UV exposure at Mauna Kea's summit the moment you step into the sun.
Bring warm clothes with wind protection. That's right, it can be cold and windy up in the saddle, particularly if you go up Mauna Kea or Mauna Loa.
Check out the W. M. Keck Observatory headquarters in Waimea. I hear the astronomical data processing center there offers interesting tours, including displays of current Keck images. That's a lot more than you'll get on Mauna Kea.

Saddle Gallery

To End of Gallery

sad00.jpg 200.03 KB	The first of a 2-frame panorama shows the east limb of Mauna Loa ("long mountain") looking south from a colorfully oxidized 3,000-year-old spatter rampart built by the oldest and farthest-flung of Mauna Loa's fissure vents. The axis of the rampart aligns roughly with Mauna Loa's summit. The bumps on the otherwise smooth east limb are the pyroclastic cones of Mauna Loa's northeast rift zone (NWRZ). The Saddle Road makes a sharp jog south here along the rampart. Spent military bullet casings were everywhere underfoot at this site, just within the Pohakuloa Military Training Area. Alas, the repeated explosions I heard nearby were not volcanic.
sad01.jpg 203 KB	The west limb of Mauna Loa from the same vantage. Lacking a major rift zone, the west limb is much smoother than the east. My freebie panorama stitching software QuickStitch wouldn't line up Mauna Loa correctly. Maybe yours will.
sad12.jpg 62 KB	The out-of-this-world candy selection at the Onizuka Center for International Astronomy Visitor Information Station at 9,300' on the Mauna Kea Road.
sad02.jpg 56 KB	The lower tier of the Mauna Kea ("white mountain") summit complex, looking NW from the upper tier. Left to right are the recently inaugurated Subaru 8.2 m single-mirror optical telescope, the Keck I and II multi-mirror visible and infrared pair and the NASA Infrared Telescope, all atop an oxidized cinder cone of Mauna Kea's capping stage. On the horizon across the Alenuihaha Channel is Maui's youngest volcano, Haleakala ("house of the sun", 10,025 ft), last active in 1790. Now 225 km NW of the hot spot, Haleakala is 100,000 years into its post-erosional stage of rejuvenated and usually explosive volcanism.
sad03.jpg 61 KB	The largest of the upper-tier observatories at the true summit, here looking north. The friendly construction workers I encountered nearby drive up to the summit (13,796 ft) daily from homes at or near sea level. I'm short of breath just walking around up here, and they're doing heavy labor. What an unusual physiology they must have developed on this job!
sad04.jpg 196 KB	Pu'u Poliahu ("hill of the snow goddess"), a capping phase cinder cone with its summit and crater intact. The cone's asymmetry reflects the direction of the prevailing northeasterly tradewinds. In the distance to the WSW is Kona's Hualalai volcano (8,271 ft), also in the capping stage. Many cones just like Pu'u Poliahu here rough up its profile.
sad05.jpg 213 KB	The majesty of Mauna Loa, looking south. Dark flows of 1843-1942 vintage have dripped down from the NERZ. The semi-circular ridge in the middle ground is a glacial moraine from the Wisconsinan ice age. Glaciers last covered the summit about 20,000 years ago.
sad06.jpg 214 KB	To maintain the thermal stability of the mirrors and instruments, Keck visitors are restricted to this small glassed-in viewing area beneath Keck I. It's hard to convince yourself you're looking at a telescope through all the steel girders and cables. The only thing I could tell for sure was that this was all very expensive.
sad07.jpg 188 KB	The entire Mauna Kea summit complex, now looking back to the east from Pu'u Poliahu. At this altitude, you're above 60% of the atmosphere, which is great for seeing but so-so for breathing. The volcanic bombs littering the foreground slope of cinder testify to the explosive nature of capping phase alkalic eruptions. Such pyroclastics cover most of the summit area. Exposed flows like the one to the right of the small silver dome are the rule on Mauna Loa and Kilauea but are uncommon up here.
sad08.jpg 183 KB	Looking NW from Mauna Kea's summit in the direction of Pacific Plate motion relative to the hot spot, Maui's Haleakala volcano dominates the horizon. Directly in line between these two giants and barely visible through the clouds is the summit of Hawaii's oldest shield volcano, Kohala (5505 ft), last active 400,000 years ago and now in its final erosional phase.
sad09.jpg 61 KB	Is there an emergency evacuation vehicle where you work? The dome houses a radio telescope. Hundred mile an hour winds, blizzards that last for days, UV radiation you can feel, 4,000-year-old cinder cones that probably won't explode again, the world's largest active volcano for a neighbor—what's to worry?
sad10.jpg 58 KB	Subaru—built and owned by the Japanese government, not the car maker—is to the left of this light pollution control sign; the Kecks are on the right. "Subaru" is the Japanese name for the beautiful open cluster in Taurus we call the Pleiades.
sad11.jpg 62 KB	Big holes cut to appease the wind didn't save this sign from a backbend. Believe both messages.
sad15.jpg 57 KB	This is the first shot of a 5-frame low resolution (640x480) 135° panoramic sweep from northeast to south, taken a little below Mauna Kea's summit.
sad16.jpg 55 KB	With oxidized cinder cones and tephra dominating the highest reaches of Mauna Kea, everything looks rusty. Mauna Kea means "white mountain", no doubt for its frequent snow cap, but "red top" would have been another good choice. This coloration is evident even at a distance.
sad17.jpg 57 KB	An oxidized capping phase cinder cone capping Mauna Kea.
sad18.jpg 54 KB	Ever-present clouds lap onto the windward coast at the foot of Mauna Loa. Hilo, socked in as usual, is behind the cinder cone at left.
sad19.jpg 54 KB	Looking south now, Mauna Loa's Mokuaweoweo Caldera is visible at the summit. At 4 km wide and 180 m deep, the caldera is similar in area to Kilauea's but not as deep.
sad20.jpg 184 KB	Now a high resolution (1280x960) version of the same 5-frame 135° panoramic sweep from a slightly different vantage.
sad21.jpg 202 KB	Similar to sad16.jpg.
sad22.jpg 195 KB	Similar to sad17.jpg.
sad23.jpg 198 KB	Similar to sad18.jgp.
sad24.jpg 197 KB	Similar to sad19.jpg—my best shot yet of the Mokuaweoweo Caldera at Mauna Loa's summit.
sad25.jpg 64 KB	This 2-frame panorama shows the eastern half of the Humuula saddle. Unfortunately, the photo doesn't do justice to the beautiful deep reds and greens of the forested lower Mauna Kea cinder cone at left center.
sad26.jpg 59 KB	The cinder cones in the saddle here all belong to Mauna Kea. Might they reflect passage of the hot spot and the transfer of the torch to Mauna Loa?
sad27.jpg 62 KB	Tilted beds of black lapilli (pea-sized cinders) below the Mauna Kea summit.
sad28.jpg 62 KB	More colorful pyroclastic beds further down the road. Note the discrete red bake zone formed when the dark gray rubbly a'a flow overran the pale red pyroclastics at road's edge. The deep weathering of the a'a reflects the extreme climate here and the 4,000+ year age of the flow. Compare, for example with the ca. 1970 Mauna Ulu a'a flow seen in nap16.jpg on the Napau Crater Trail page.
sad29.jpg 61 KB	A 2-part low resolution panoramic sweep of Mauna Kea looking north from the foot of Mauna Loa, just above the Saddle.
sad30.jpg 59 KB	The weathered a'a in the foreground is probably prehistoric.
sad31.jpg 60 KB	Endless pahoehoe from a Mauna Loa flow (1899?) stretching to the horizon, here looking upslope to the southwest. Distant cones dot horizon along Mauna Loa's NERZ.
sad32.jpg 63 KB	The same pahoehoe flow, now looking downslope and northeast to the saddle.
sad33.jpg 61 KB	This 8-10 m tube skylight well down a pahoehoe flow (1899?) at the foot of Mauna Loa looks to me like it hosted a fountaining breakout at one point. Note the drainback glazing at the lips and the spatter ramparts beyond.
sad34.jpg 59 KB	A close-up of the same skylight.
sad35.jpg 65 KB	An even smaller breakout nearby, less than 1 m across and at least 2 m deep. Presumed cooling cracks form a polygonal pattern on the drainback surface at bottom.
sad36.jpg 63 KB	Mauna Kea's north flank, this time at low resolution. Oxidized tephra from capping phase eruptions impart the reddish color at the top.