Upper level stream crossings can mean two different, but not mutually exclusive things: moving water crossings higher than the knee of the person walking, and crossings far from the assistance of others. Discussed below are several levels of analysis one should bring to such things.
Preparation and assessment is important. It may not be realistic to have a list of all potentially problematic crossings and their solutions, but in the age of satellite photos there is little reason to not do your best.
Volume is the first and most obvious factor. In the lower 48 there is a good chance that some river or creek in the drainage basin has a gauge on it. Find out how close to flood that stream is often running at the time of year you plan to be there.
The drainage basin is the second factor. How big is the basin, what percentage of the aforementioned river volume does it constitute? Insofar as many problem crossings have to do with snow melt, what is the altitude and aspect of this basin? South facing stuff will melt out faster under solar influence, and so forth. Different altitudes melt out at different times. Estimate how much water might be coming down a particular drainage.
Gradient has a massive influence on difficulty, as folks the other weekend found out. All other things being equal, steeper is harder, both because the water will be faster and because the channel will probably be narrower and thus harder to move up and down.
Vegetation can have an influence on crossing difficulty, insofar as burnt trees can end up in larger drainages and provide bridges. Not a good thing to count on, for reasons to be addressed.
Geology is perhaps the more important factor, perhaps moreso than volume and drainage (if only because that datas use will depend on previous on the ground experience). The surface under your foot will make an enormous difference in strategy. A fast, waist deep crossing with a uniform gravel bottom is pretty easy. The same on basketball to microwave granite cobbles is terrifying.
Find this stuff out before you go. Sat photos will even allow for site-specific scouting in many cases. If the photos are recent that awesome log jam might even still be there.
Once you’ve done your homework and selected a route with crossings that are in theory doable, it is time to put things into practice on the ground.
I’m not a big fan of the conventional wisdom which says to keep your pack loose and unbuckled. It is true that a big (>1/5 body weight) will make it tough to get up if you go down in fast water. It is also true that unless you’ve done some serious training, such a pack will make a hard crossing much harder simply by virtue of added weight. Having it loose and floppy will only make this worse. I’ve also never been especially clear what you’re supposed to do if you shuck your pack in a crossing. Look for it downstream? Keep essentials in your pockets and have a long, hungry walk out? Better to keep a light pack, keep your pack on and well cinched, and if you must carry a big pack (hunting, field research) factor that into trip planning. You might need to take a different route, or go at a different time of year, or bring more people and/or different gear.
Any upper level crossing requires special preparations before you get wet. Putting on shell clothing and perhaps a warm hat or vest won’t keep you from feeling the cold water, but it will blunt the shock and save some body heat and function should the crossing take longer than you think, or if you go under. Everything which needs to should be sealed in waterproof bags in your pack, and the pack should be compressed tight. You want the pack to be as low profile as possible should the water come past your crotch, and you want the pack to absorb as little water weight as possible. You should trap some air in your dry bags and/or pack liner, but not too much. Some buoyancy in the pack will help in particularly deep water, but too much will make it harder to keep your head up if you have to swim. Lastly, it’s a good idea to have some essentials in waterproof storage in your person. Firestarters, headlamp, map, and a few snacks. Whatever you’d need for self-extraction should you have to discard your pack.
It hardly needs to be said that crossing specific shoes like sandles and crocs are not appropriate here. You want the best traction possible for difficult conditions, so just get your shoes wet. One pole is a good idea, provided it is stiff enough to take body weight. Two poles are harder to control. Remove larger pole baskets, as they cause problematic drag. Clothing, especially pants, should be trim for the same reasons.
Crossing strategy will be determined by the environmental factors mentioned above, in combination with your own mental and physical abilities. Scouting for a location can take some time under difficult circumstances. In the lower 48, most trail fords have been wisely placed, as the requirements of pack trains and hikers are much the same. It’s worth reading Andrew and Jon’s Open reports for their accounts (and Jon’s photo) of crossing Lodgepole Creek. As can be seen from the map, Lodgepole doesn’t have too much gradient. It does have a big basin, and small slick cobbles on the bottom. Greg Gressel crossed at the lowest spot, which is steeper and a bit shallower. Greg lost his feet on that one. I crossed at the main, lower crossing. Andrew, Chris and Jon crossed on a log not far below the upper trail. Their thought process, that the upper crossing might be gentler, was a good one. Lodgepole was just blown out with a lot of melt coming out of its big, south facing basin. Above Morrision Creek the flow might have been a bit less, but the character would have most likely been little changed.
I crossed Lodgepole facing upstream, with a single stiff trekking pole lengthened to around 135cm. I had both hands and a lot of body weight on the pole. The last 1/4 was the deepest and fastest. For the first 3/4 I angled upstream, while for the last 1/4 I let the current take each step a little backwards.
I prefer to make upper level crossings facing downstream whenever possible. Fighting the current by facing upstream takes a lot of energy and is slower, prolonging exposure to cold and further sapping energy. However, foot entrapment is a huge safety concern during high crossings, and for this reason I face upstream and strive for deliberate foot placements when dealing with cobbled and bouldered stream bottoms, which in NW Montana are the rule rather than the exception. If you loose the upstream fight against the current, pivot quickly and face downstream, tap dancing frantically to keep toes clear of crevices.
For crossings with graveled, sandy, or muddy bottoms, a strong diagonal facing downstream is a my preferred method. A stronger current will increase the ratio of downward to sideways travel. Lean upstream into the current and drive your heels in, propelling yourself sideways and allowing the current to force you downstream. Below crotch level this technique is pretty trivial. Once your pack and butt are underwater the force of the current will speed up the process quite a bit, and by the time your ribs get wet you’ll likely be in intermittent contact with the floor. This is fine, maintain directional velocity and go with the flow. If/when you loose your feet for a while, lean into a backstroke and enjoy the floatation provided by your pack.
This technique works well for rivers and streams with muddy bottoms and quicksand, as your never putting too much pressure on any foot, and can lean back into the current for leverage when pulling a foot free.
Scouting a good crossing is vital. Shallower water, good bottom conditions, and most especially plenty of clear water downstream. Sweepers, strainers, and rapids should be well avoided. Whatever your margin for error, double it.
The most difficult crossings will be those which do not offer good options. The crossing in the above photo was one of those. The bottom was slick cobbles, the current swift, and the water dark with glacial silt. There wasn’t a safe place to cross (though if the water had been clear it probably would have gone), and the creek was too swift and boney to packraft. Josh Mumm, Luc Mehl and I bushwacked and climbed along the near bank to the confluence, where more water allowed for decent boating (though there was a must make ferry immediately upon launching). Roman Dial, a more confident boater, put in a bit lower down from this photo and rafted the creek. A packraft will open up options for many difficult crossings, but is not a universally problem-free solution.
Another tough crossing was 25 Mile Creek during the Bob Open the other weekend. As the map shows, 25 Mile is steep. It is cobbled. The drainage isn’t huge, but much of it does face south. Greg Gressel crossed a bit above the trail, climbing through a steep section split into three braids. None of those crossings would have been more than 8 feet wide, but the rocks were bigger and the swim uglier if you lost your feet. Cyrus and Kate inflated boats and rafted around the creek on the Middle Fork, a safe option I seriously considered. Andrew, Chris, and Jon took the path I outlined on the map; bushwacking up to a flatter spot where they crossed with little difficulty. The volume of 25 Mile was probably only 2/3 that of Lodgepole discussed above, and thus not too bad when given a reasonable gradient. I crossed at the trail, facing upstream and taking an upstream diagonal. The strongest current was at the far side, and my upstream path gave me the furthest margin of error should I have lost my feet at that point. A swim through the steep riffles below would have been bruising, and a good place to snag a foot.
I’m not a big fan of log crossings. They have to be really good to be safe, and often tempt you into high consequence, all or nothing situations.
Group crossings can make a big difference, especially for shorter and lighter group members. Communication and coordination difficulties make many traditional ideas better in theory than application. The two stack for upstream facing works well, with one person behind the other holding on to shoulder straps, but it can be hard for the second person to see their feet. Most of the time I think individual crossings are best, with the most at-risk person in the middle with spotters on either side of the stream. A throw bag can even be handy here.
Pinchot Creek near flood; steep, fast, big boulders, and just small enough to tempt you into trying. No good alternatives for miles upstream. Not worth bothering under these conditions.
To review, preparation and practice are crucial for safe upper level crossings. The best way to practice is on rivers, during a hot summer day. Push the limits and swim when it is safe and comfortable to do so. 30 miles from the road, tired and cold is not a good place to do something for the first time.
In the field, calculation and restraint must come first. Better to hike out than hurt yourself. At the same time, indecision and timidity will only cause problems. Once you decide you can do a crossing, do so boldly and with full commitment. As with most things, safety is primarily created by the mind.