In the last HCRH milepost visit we had a look at Milepost 32, the one right at world-famous Multnomah Falls. This time around we're a mile east of there, at Milepost 33, and it could hardly be more different. Instead of a world-famous crowded tourist attraction, we're visiting the scene of an expensive and embarrassing accident from the 1940s that was quickly papered over and forgotten by just about everyone.
It seems nice enough here; there's a rare flat grassy area right next to the highway, and even a small turnout right at the milepost, just big enough to park a small car or two. If you stop here and walk to the other end of the little meadow to where the trees start, you'll notice some old concrete barriers that are somehow not visible from the highway. Continue past them into the trees and suddenly you're on an old gravel road. Not just a trail, an actual road, gently angling up and away from the highway. So today we're going to look at where this road goes, and the dumb idea behind why it was built, and what happened after that.
A bit of background first: The famous Columbia River Highway opened in 1916, and thanks to the magic of induced demand it was quickly swamped by big trucks and other commercial traffic, and drivers of all sorts who just wanted to get to Point B as soon as possible and had zero interest in the road's meandering curves and scenic vistas. Before long the state Highway Commission -- today's ODOT -- started planning a new highway route that would traverse the gorge close to river level and as close to a straight line as was possible while still following the river. The problem with this idea, and the reason why the original road didn't do this, is that in general, the needed freeway-width flat land along the river just didn't exist, and you either had impassable swamps, er, wetlands, or sheer basalt cliffs that dropped straight into the river. The mid-20th Century solution to this problem was to simply dump gravel into the river until you had enough new land, and then build your sleek modern freeway there. (That's probably going to end badly at whatever point Big One -- the 9.0 earthquake they keep telling us is coming -- finally occurs. At which point the whole freeway probably liquefies and slides into the river. But hey, we had a good run.)
Bragging about I-84 has long since gone out of fashion, so I don't know how many million or giga-gazillion tons of gravel were used in this project. And I'm not going to hazard a guess, for the same reason I've never won one of those contests to win a big Mason jar of candy corn by guessing how many candy corns the jar contains. (Also I hate candy corn and would rather not win a big jar of it, thanks.) Obtaining that much gravel seems to have been the gating factor on how quickly they could build the new highway, and then one day someone looked around and realized the gorge is full of steep talus slopes composed of loose rocks, already about 80% of the way toward being the gravel the project needed. In fact there just happened to be a huge talus slope roughly one half-mile east of Multnomah Falls, and if enough of these rocks could just be moved a short distance downhill to the river, and then crushed into proper gravel, it would be a huge time saver. Some members of the general public raised a few questions about this idea, but in December 1939, the Oregonian assured readers that the gravel operation would not be an ongoing eyesore:
At a point a half mile east of Multnomah Falls, where Contractor G.D. Lyon needs 535,000 yards of rock to build a two-mile toe along the river’s edge, a haul road, 1900 feet long, is being built into the great rock slide which will provide material with a minimum of blasting. The natural tree and shrub screen between the present Columbia River highway and the haul road will not be disturbed,except at the point where the latter crosses the former. Plans already are made to augment this screen with additional plantings so that eventually the cut will not be discernible from either the present or the new water highway.
And going by that criterion alone the project was a rousing success. You could drive by this spot every day for years and have no idea the old digging site was here. For a better idea of what they were planning, check out this ODOT project map, dated October 1st 1940 (see page 7), and note that it closely matches the LIDAR image below:
This is what the area looks like on the state LIDAR map. From what I've been able to figure out, the little parking lot next to Milepost 33 is where the old haul road crossed the highway, and the survey map shows that the grassy area was part of a small temporary detour so the haul road could slope downhill right through where the highway normally was. And you can see the road continuing east and downhill to the railroad, right next to present-day I-84.
The other end of the road -- which we were hiking on before that extended tangent -- ends at the big talus slope east of Multnomah Falls. You might see some water trickling out of the base of the talus slope. At this point you're just a few feet downhill from where Trail 400 crosses the talus slope, as well as the start of the the infamous Elevator Shaft trail. If you look closely at the lower left corner of the image, you can even see a part of the trail, which climbs that talus slope in a seemingly endless series of tight switchbacks. I've read there are over 100 of them overall but have never tried counting them myself, either on the map or in person. LIDAR seems to show a couple of additional switchbacks continuing down to the highway, as if there was (or still is) a way to start the ascent from down there somewhere, maybe from a car dropping you off.
But back to our story. Work on the river-level highway paused during WWII and resumed afterward, and so we skip forward to February 1946, when a gigantic landslide covered the old highway and the railroad (and the spot we were just standing at in the last paragraph) in a massive pile of rocks for several hundred feet. (more photos on page 26 of that issue). News updates continued over the next week: A followup article the next day noted that even more debris had come down since the initial article. One photo has the position of the road drawn in as you wouldn't otherwise know where it was. The stream draining the Elevator Shaft watershed had an impressive canyon at that point. Another followup on February 8th notes that roughly another million tons of rock had come down just overnight, and it was the worst landslide the Highway Commission's Gorge operations had ever encountered. A further update on the 11th included another photo of the geological mayhem.
Today there aren't any obvious signs of what happened from the road -- if you got here coming from the west, you passed right through the site of the slide half a mile before Milepost 33, probably without noticing anything out of the ordinary -- and it's also hard to visualize where the slide happened or just how big it was by looking at present-day maps. Historic Aerials imagery from 1953 shows the slide site pretty clearly, as the recently-exposed rocks are visibly lighter than the rest of the talus slope.
I haven't figured out exactly how long the highway and railroad were closed, but it obviously would have been an extended period of time. Union Pacific was understandably apoplectic about this nonsense, and sued for damages in August 1947. The case was settled in 1950 with terms not disclosed immediately. The suit had alleged the slide was caused by human error:
The slides covered the main line, burying some 250 feet of track to a depth from 20 to 30 feet. The company contended the slides were caused by highway workmen who disturbed the natural repose and natural drainage of a mountain slope a half mile east of Multnomah falls.
So what does that mean? Suppose you are in a place with gravity, and you have a pile of objects. Could be just about anything: Football-to-watermelon-sized basalt rocks (to pick a random example), but also gravel, dry sand, wet sand, snow, coffee beans, ball bearings, Legos, holiday party rum balls, $100 bills, tapioca pudding, skulls of one's enemies, etc. No matter what it's made of, there's always a maximum angle that limits how steep your pile can be, determined largely by object shape and friction between individual objects in the pile. Increase the angle beyond that -- add more things to the top, or remove some from the base -- and now your pile is unstable. At that point things will tend to tumble down the sides of your pile and accumulate there, decreasing its steepness until it's back in equilibrium. Or to put it in fantasy novel terms, the Oregon Highway Commission and its contractors coveted gravel above all else, and in their quest for more of it they delved too greedily and too deep, and instead of awakening the local Balrog (a demon of the ancient world), they awoke the universal laws of gravity, with predictable consequences.
I was about to say something to the effect that everyone learns this early on when playing outside, like the time you and your friends decided the big gravel pile at the construction site down the street was Mt. St. Helens, and kicking rocks away from the base was how you made it do realistic landslides. Eventually it would be time for a full-on eruption, and then you'd just throw gravel at each other until you got bored or someone got hurt. But that was 1980, which I have to admit was a long time ago now. In 2025, any adult who sees you doing this will call the police, and Officer Friendly will come and shoot you, and your parents, and your friends, and their parents. And everyone in the Nextdoor group for your neighborhood will be in smug agreement that you totally had it coming, and you got what you deserved for going outside ever. Playing with gravel in 2035 will have a similar outcome, except it'll all be done with AI drones rather than Officer Friendly shooting you in person, supposedly for force protection reasons but really because it's cheaper and it scales up really well.
Anyway, the story ends the way a lot of stories do that involve corporations and government agencies: There's an undisclosed settlement, the involved parties never speak of it again, the incident goes down the memory hole and is quickly forgotten, and then nobody learns anything from what happened or tries to do better next time. The End. And on that cheery note, we're off to milepost 34.
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