Fall Hiking in the Wallowas: Hurricane Creek Trail and its geology

Published 8:58 am Thursday, September 8, 2016

The French author and philosopher Albert Camus famously said: “autumn is a second spring when every leaf is a flower.”

Autumn is also one of the best times to explore the Wallowas. In the backcountry, tamaracks and aspen spread gold across the landscape, while gooseberry and vine maples dress in scarlet. The weather is crisp. Hikers are rare. Mosquitoes have vanished. Occasionally it rains. In high country, snow is likely.

There are plenty of great trails to explore. Hikers keep trails up the East and West forks of the Wallowa River trail open and tamped down through most of winter; the road to the trailhead is plowed after every snowfall, making the paths accessible year-round. (Insulated, waterproof boots are a must for navigating the snowy trails.)

With a gentle gradient and long traverse into the Wallowas, the Hurricane Creek Trail (Forest Service Trail 1807) provides an especially appealing fall entrée into the Eagle Cap Wilderness. By mid-October tamaracks and aspen brighten the forest. Songbirds are gone, but an occasional elk bugle can fill the silence with its own melody. Mountain goats and bighorns tend to graze lower on the slopes and are more easily spotted by hikers. There’s an autumn crispness and the scent of leaves lingering in the air.

The Lakes Basin is a little more than 10 miles from the Hurricane Creek trailhead. When snow falls, Hurricane Creek Road is plowed only to the Forest Service boundary, still 5 miles from the trailhead, so be aware of weather and road conditions when you drive in. The good news is that the un-plowed Hurricane Creek Road makes for a nice winter walk or cross-country ski route once the white fluffy stuff covers the ground here.

Before the snow flies, the Hurricane Creek Trail and its side trails up Falls Creek, Thorn Creek and to Echo Lake offer superb encounters with geology. Along the 3-mile hike (6 miles round trip) from trailhead to Slick Rock Creek, you’ll see most of the rock types that comprise the Wallowas. Continue to about 8 miles up the trail and you’ll see everything geology has to offer.

The Hurricane Creek Trail starts in the oldest rocks of the Wallowas — ancient volcanic rocks known as greenstones. They form the base of the mountains. Approximately 240 million years ago they were part of islands off the Idaho coast. Today, they peek out of one or two places along the trail just past Falls Creek. Greenstones are unpretentious rocks — dull in color and more gray than green to most eyes. Commonly, you’ll find rectangular white specks or blobs in them — original minerals that have been altered from clear feldspars to opaque white clays and micas by heat, pressure and time.

Once across Falls Creek, you’ll also enter the 400-acre area burned by the August 2015 Falls Creek Fire. Control and containment measures included water and borate drops and the distribution and use of almost 5 miles of hoses.

As you climb away from Falls Creek a view to the southeast opens and Sacajawea, the Wallowas’ highest peak at 9,838 feet, appears. It’s a gray-colored mountain, composed almost entirely of marble. To geologists, marble is nothing more than limestone that has been metamorphosed — recrystallized by heat and some pressure. The light-colored, gray rocks that comprise Sacajawea, Matterhorn and the lower portion of Hurricane Divide to the west are all limestones that were metamorphosed by the intrusion of the “granites” that form the core of the Wallowa Mountains. These limestones (now marbles) are about 200-230 million years old. In places where they are less altered they contain fossils, including corals and “clams.” But fossils in the rocks of Sacajawea, Matterhorn and Hurricane Divide have been obliterated by heat and pressure.

In addition to being the highest peak in the Wallowas, Sacajawea also rises 1.2 vertical miles (6,377 feet) from its base on Hurricane Creek. The climber’s website Peakbagger.com says it is the second most prominent peak in Oregon. Only Mount Hood rises higher above its surrounding terrain.

As the landscape opens to views of Hurricane Divide west of the trail, you’ll see dark layered rocks atop the gray marbles. These are sedimentary rocks — mostly sandstones that, like the marbles beneath them, have been heated and metamorphosed. The marbles and banded or layered “sandstones” appear along the trail, especially at stream crossings.

You’ll also notice narrow streaks of dark red-brown rocks that slice through the gray marble. These are basalt. Specifically, they are the fissures or “dikes” that allowed dark, fluid, iron-rich basalt lavas to reach the surface (far above today’s peaks) and erupt. The eruptions — about 14-16 million years ago — produced the Columbia River basalts, the lavas that covered the Columbia Basin, and flowed all the way to the Pacific Ocean.

You can get up-close and personal with one of these dikes at Slick Rock Creek. About 3 miles into the hike, the trail switchbacks and then creeps along above a steep, narrow gorge sliced into marble before leading to Slick Rock Creek. Here, a waterfall cascades over a dark cliff. The dark cliff at Slick Rock Creek is part of a Columbia River basalt dike.

Beyond Slick Rock Creek you’ll find patches of open meadows that open views of granite peaks to the south, and finally, the marble face of Matterhorn. The dark lines that mottle its north face are more Columbia River basalt dikes. The vegetation begins to change. Subalpine fir increases, Douglas fir decreases and Ponderosa pine vanishes. Large Engelmann spruce are the patriarchs of the valley floor.

“Granite” outcrops don’t appear along the trail until about 8 miles into the 10-mile trek, at the threshold of the Lakes Basin. These black-and-white, speckled rocks are about 120 million years old — much younger than the greenstones, marbles and “sandstones” but much older than the basalts. Granites, strewn with dark red-brown basalt dikes form the core of the Wallowas, and occupy the entirety of the Lakes Basin.

If you venture into the Wallowas in the fall, be sure you are prepared for cool to cold, wintry mountain weather. This means base layers and mid-layers of clothing that will keep you warm. Also, waterproof, insulated boots, hat, warm gloves, warm and waterproof jacket(s), fire-starter and stove, water, flashlight and/or headlamp, shelter and extra food at a minimum are in order.

Be sure to let someone know where you are going, and when you will return.