How to Ford a River
Reprinted as seen in the September+October 2009 issue of Washington Trails Magazine, written by park ranger, Ralph Radford.
We’ve all heard the old joke about the chicken crossing the road. You could tell the same joke about the hiker and the other side of the river. It’s important to ask this question before attempting to cross a river: is the risk worth the reward? Probably. A successful river crossing just calls for taking some safety precautions first and having a basic understanding of how a river works.
River hydraulics for hikers
Various objects, such as rocks, soil and tree ruts create different levels of fiction in a stream. This, in turn, creates different water surfaces called laminar flows.
The basic principle is that various layers or channels of water move at different speeds. The lower layer of the river moves more slowly than the top layer. The layers next to the bottom and sides are the slowest; each subsequent layer will increase in speed. The top layer of the river is only affected by the air. The fastest part of the river will be just below the top layer of the river.
For hikers, this means that your feet can have good traction on the river bottom below, but your knees will take the full brunt of the force of the current, which could knock you over.
Test the river's hydraulics
You can test river hydraulics by sticking your trekking pole or stick in the stream to feel the current pressure. You can also throw a stick in the river and see how quickly it moves downstream. Track the stick, see if gets stuck in a dangerous vacuum or suction hole. If you do fall in the river, your path will normally follow the path of the stick.
Selecting an area to cross
Once you have made up your mind to cross a river, carefully study the river looking for a place to cross. If there is a high vantage point above the stream, climb up and survey the river. Note points where you can get out of the river if you fall in and are swept downstream.
Select an area that leads across the current at a 45 degree angle going downstream. It may be easier to cross if the river is broken into smaller channels with shallow banks and sandbars. Look for animal tracks such as deer or bear in the sandbars; this would indicate that large animals are able to cross this area safely and the water is moving slow enough to be used as a drinking hole by animals.
Getting yourself prepared
- Loosen your straps on your pack; if you get knocked off the tree, you need to get rid of your pack quickly. (Keep in mind that one downside to this tactic is that your backpack will shift on you, throwing your balance off during the crossing.)
- Don’t cross barefoot, this will lead to injury from sharp rocks and sticks. Use an old pair of tennis shoes or surf shoes when crossing.
- Tie your hiking boots together and drape them over your neck or tie them to your backpack.
- Don’t use a rope when crossing a river. If you are tied to another person and that person falls in, they will tend to also pull you in.
Other crossing methods: logs, boulder hopping and more
Use a log. One way to cross a stream and keep your feet dry, too, is to find a tree that has fallen across the river.A tree with the bark on it will provide more traction for your feet than an older tree, stripped of its bark and slicked up with a layer of green moss. Face upstream and sidestep as you cross the log. Don’t stare at a fixed point. Rather, keep your eyes moving to help stop vertigo. Crossing on a downed tree with a large backpack will be a bit more difficult, as the branches tend to snag your straps or make it tricky to squeeze between two limbs.
Boulder hopping. Another crossing method is boulder hopping or rock jumping. I use this method most often, as it is hard to find a fallen tree that crosses an entire river. Boulder jumping requires good balance, quick reaction to loose rocks and a light pack.
- Scout your route and figure out where your hands and feet are going before taking that leap of faith.
- Try to keep three points of contact at all times.
- Jumping up to a boulder is easier than having to jump down on a rock because you will have more momentum and gravity pushing you along when hopping down.
- Having a stick or trekking poles will help you out during your balancing act.
- Many of the rocks may look safe to cross on, but, remember, most of these rocks have been underwater for a long time. Their unseen slime layer can throw you into the river.
Not recommended: log jams. With all the storms that we’ve had in Washington over the past few seasons, there are quite a few log-jams that can be used for crossing. Log jams are extremely dangerous to cross. If you fall in during this crossing, you can be swept under and pinned down under the trees and water. Log jams consist of logs and brush collected from a high flood. The jam will stay stationary, while the river runs under it or between the logs. The difficult part of any log jam is getting around the large tree root balls that are sticking up. You may have to swing around the root ball, grabbing a protruding root off to the side. Loose rock and soil from the root ball may fall down on you as you grab the roots.
Unpractical pole valuting. One last method to mention, which is not at all practical, is to pole-vault your way over the river. I’ve actually only seen this method used on one of those survival shows on television. First, you have to find a long, strong, straight branch about eight feet tall. And, that’s the first problem, because you then have a lot of sawing to do. Once that’s done, you are going to have to find a narrow part of the channel of the river and then run with your pole, jam it into the rocks and vault yourself to the other side. Good luck with that!
If you fall in on your crossing
If, despite all your preparation, you do fall in, point your feet downstream and float on your back, paddling with your hands towards shore.
But, let’s presume you make it across the stream successfully. Unless you’re hiking one-way, you’ll have to cross it again on your return.
- Mark the crossing point.
- Remember how much time it took to cross, so you can factor in the time it will take to cross back over before darkness.
- If you’re camping for an extended stay, be sure to remember that a river can flood or have spring melt-off and your crossing point may be gone for several weeks. The book “Into the Wild” illustrated this point all too clearly, as a flooded river leads to the demise of the camper.
No matter how you get across, river crossings can add excitement and adventure to your hike. Use some common sense and you won’t get all washed up.
Ralph Radford is a park ranger and WTA member from Seattle.