Vagabonding on Dangerous Ground: The Geology That Explains Why North Cascades is a Park Divided

Diablo Reservoir below the peaks of North Cascades National Park. The Turquoise color results from fine silt and clay derived from glaciers.

As I described in my last post on vagabonding, North Cascades National Park is the most strikingly beautiful national park I visited but never set foot in. The reasons become immediately clear with a look at the map of the park. There are two roadless sections, the North Unit and South Unit, and they are separated by the Ross Lake National Recreation Area along the Skagit River. And we unfortunately didn't have enough time for extensive hiking.

The human reason for the separation of the two park units is explained readily enough. Most national parks are established for their wilderness, geological, biological or historical values. They are not generally established to praise the engineering works of humankind. There are a series of dams and hydroelectric generating facilities in the Skagit River Gorge, and as such, they are administered as a series of national recreation areas. All of the parks and recreation areas were established at the same time, and are jointly administered by one bureaucracy. Because of the easier access (i.e. actual paved roads), the recreation area receives 750,000 visitors each year. The national park is visited by around 20,000 people a year. It would be fair to say that most of the visitors to the Ross Lake unit are there to appreciate the beauty of North Cascades. From a distance...

It turns out that geology had a lot to do with the circumstances leading to a separation of the two park units. We put dams where they will store as much water as possible, and that usually requires the presence of large rivers and drainage basins. Were it not for a geological event a few hundred thousand years ago, the Skagit River would have not been an appropriate place for a series of huge reservoirs (Ross Lake, for instance, has a capacity of 1,435,000 acre-feet of water. The lake is 22 miles long and extends into Canada). Prior to the ice ages, the Skagit River was a relatively small river, and the drainage did not cross the divide between the two park units as it does today. Instead, the ancient headwaters of the Skagit flowed northward into Canada, becoming part of the Fraser River drainage.

The ice ages put an end to that. A huge lobe of ice flowed south out of Canada, blocking the flow of the upper Skagit. The river backed up into a large lake, and eventually the lake breached the rim at a different location and started flowing west. The meltwater from the glaciers added to the ability of the river to carve downward, and the Skagit River Gorge was quickly cut (at least in geological terms). The river that flowed west was now many times larger, and the Skagit Gorge was too much of a temptation for any dam engineer to resist. Three reservoirs were built, Gorge, Diablo and Ross, and today they provide around 20% of the electricity used in Seattle.

So, today we have one of the most beautiful alpine regions in the Pacific Northwest, and a once small river made far larger by a quirk of geological history. It was a marvelous sight, but there was more. We drove beyond Ross Lake and headed for the high passes beyond. More next time...

Vagabonding on Dangerous Ground: Our Tour of the Greatest National Park I Never Once Set Foot In

Photo by Mrs. Geotripper

The western slope of the Cascades Range is green. Very green. There are trees, shrubs, mosses, grasses, just about every kind photosynthesizing plant there is. This is due of course to the mountains themselves. They provide a barrier to incoming Pacific storms, causing the moist masses of air to rise and condense, with copious amounts of rain and snow falling to the ground. We were still in the realm of the rainforest.

Photo by Mrs. Geotripper

We were on the southbound road towards home following our exploration of the coastal belt of the Cascadia Subduction Zone. We were on vacation, but we happened to be in the region when the New Yorker article about the coming magnitude 9 earthquake hit the stands. All of the sudden, it was the talk of the town (if you were in Seattle or Portland, anyway). So our trip became a blog exploration of the fascinating geology and natural history of the region.

Photo by Mrs. Geotripper

We had spent nearly a week exploring the coastal belt of British Columbia, but now we were back over the border into northern Washington. We were inland now, following the chain of volcanoes that result from the melting of the rocks above the sinking slab in the subduction zone. We had already seen the Black Tusk and Mt. Garibaldi in Canada, and were now looking for the northernmost volcanoes in Washington. They were hard to find in the thick forest!

Photo by Mrs. Geotripper

We headed up the Skagit River to pay a visit to what I believe is the only remaining national park in the western contiguous states that I hadn't been to yet: North Cascades National Park. We found a space in the park campground, and moved on to the visitor center nearby. We weren't seeing many Cascades mountains or volcanoes. We also had not yet, and would not ever set foot in the national park during our visit.

Photo by Mrs. Geotripper

The thing is, North Cascades is a wilderness park. No roads reach the interior of the park, and the only road that crosses the range doesn't pass through park lands. The Skagit River has been dammed for power generation, and the valley between the north and south units of North Cascades is administered as the Ross Lake National Recreation Area. Our campground and the visitor center are both on Ross Lake lands. I wasn't sure how much of the park we would be able to see during our short visit. We didn't have time for long hikes, and the main road between the two units was ensconced in a steep gorge.

We could see a few peaks above the river, but they weren't the glacial alpine peaks I was expecting to see. It was deep forest everywhere. Where were the rocks?

Photo by Mrs. Geotripper

From the visitor center, a short nature trail promised a view. We walked over to take a look, and mountains appeared out of the greenery!

Photo by Mrs. Geotripper

The visitor center was on a bluff above the Skagit River, and the viewpoint provided a vista up Goodell Creek towards the Southern Picket Range. The Pickets rise to 8,000 feet, and expose granitic and metamorphic rocks that have been scoured by glaciation. Glaciers still cling to the highest ridges.

One peak really stood out from the others. It's called Pinnacle Peak, or "The Chopping Block", and has an elevation of 6,805 feet (2,704 meters). The summit area preserves a bit of the relatively flat pre-glacial topography. The ice age glaciers chipped around the edges, but didn't remove it all.

Having found some rocks at last, we started looking at the maps to see if we could find more. I had no idea what was about to come next! More next time...

Geotripper Finds Rocks in the Pacific Northwest! All is Well

Diablo Reservoir and Colonial Peak in North Cascades National Park

I admit to being just a little bit snarky in some of my recent posts concerning the paucity of rocks seen on my latest journey through the Pacific Northwest. Seeking out the rainforests was one of our main goals on this trip, and I thoroughly enjoyed my visits to Humboldt Redwoods, the Hoh Rainforest of Olympic National Park, and the forests of British Columbia. One the other hand, it is true that rocks were in short supply for the first part of our journey. That sure changed in the last few days!

Kangaroo and Vasiliki Ridges near Washington Pass, east of North Cascades National Park

I will probably write a series of blogs about our vagabonding across the Pacific Northwest, but one thing to point out is that we were attempting to explore new territory, and that included the North Cascades, a big mysterious blank area on the map of my personal geography. I've been around the mountains and seen them from a great distance, but before yesterday I had never seen them up close.

Early Winters Spires at Washington Pass east of North Cascades National Park

We pulled into the campground at Newhalem in North Cascades National Park, or more properly, Ross Lake National Recreational Area. The park itself is the remote wilderness in the peaks above the Skagit River. We then took a late afternoon driver to Washington Pass on the east side of the park. It was simply stunning! I've down a lot of traveling and seen many wonders, but my breath can still be taken away by an incredible view.

Mt. Baker and Boulder Creek (I wonder how the creek got its name?)

The next morning was a short exploration of the Baker Lake area, and one of the most interesting of the Cascades volcanoes, Mount Baker. It is one of the most active of the chain, with some minor eruptions in the 19th century. It is second only to Mt. Rainier in the volume of ice coating its summit.

The glaciers of Mt. Baker, lahars just waiting to be released.

It's been a fascinating trip (that isn't quite over yet). I'm looking forward to sharing some interesting geology in coming weeks.