River crossing basics for trampers

Plenty of New Zealand tracks have unbridged streams and rivers on them, and the water on those crossings can change within hours. The skill that matters most is not technique in the water. It is planning a trip so that you never feel you have to cross, and recognising the river that says no.

This note is a primer. It is not a substitute for learning the skills in person, and it points to the guidance from the NZ Mountain Safety Council’s river safety pages and DOC’s river crossing safety advice, which you should read in full before a trip with crossings.

Before you leave home

Find every crossing on the route. DOC track pages, topographic maps and local visitor centres will tell you where the main unbridged crossings are. Don’t forget side streams. DOC points out that even small side streams can flood and become too dangerous to cross, and they are easy to overlook because they look like nothing on a dry day.

Check the weather for the whole catchment. Rain that falls in the headwaters arrives at your crossing later, sometimes on a fine afternoon. Look at the forecast for the ranges above the track, not just the valley you will walk in. Our note on reading river flow and rainfall data covers how to use council river gauges and rain warnings.

Build in a way out. Both DOC and the Mountain Safety Council make the same point: plan time to wait and a route to turn back on. In practice that means:

• spare food for at least an extra day
• an emergency shelter
• a distress beacon, and a two-way device such as a satellite messenger so you can tell someone you are delayed
• a plan B route, or a hut you can retreat to
• a trip plan left with an emergency contact that mentions the crossings, so they know a late return might just mean high water

Pack for water. A sealed pack liner keeps your gear dry and, as the Mountain Safety Council notes, helps your pack float if you lose your footing. Double-bag the things you can’t do without, like a sleeping bag and dry clothes.

At the river: the warning signs

DOC’s advice boils down to four signs. If any of them are present, don’t cross:

• Fast — the water is moving faster than walking pace.
• Murky — it is discoloured, often brown.
• Messy — there are branches or other debris coming down.
• Loud — you can hear the river roaring or rocks rolling along the bed.

A simple way to judge speed is to throw a stick into the fastest part of the flow and walk along the bank beside it. If you can’t keep up at a normal walk, the river is too fast, however shallow it looks. Shallow, fast water knocks people over more often than deep, slow water.

Also don’t cross if you can’t find a good place to get in and out, or if anyone in the group doesn’t have the skills. That last one is the easiest to ignore when the rest of the party is keen.

Choosing a place to cross

If the river passes every check and everyone has crossing skills, the next decision is where. Spend time on this. Look from a high point if you can. Good crossing places tend to have:

• an even bed, ideally shingle
• a wide, braided or riffled stretch rather than a narrow, deep chute
• an easy way in and, just as important, an easy way out on the far side
• no logs, wire fences, undercut bluffs or rapids just downstream

Avoid places where two channels meet, because holes form there, and stretches with steep banks, which often mean deeper water. The Mountain Safety Council’s guidance is that the water should be no higher than the thighs of the shortest person in the group.

The mutual support method

For groups of two or more, the method taught in New Zealand is mutual support. The group stands close together side by side, facing across the river, each person holding the pack or hip belt of the person next to them. The strongest person goes at the upstream end to break the force of the water, with the next strongest beside them and another strong person at the downstream end. The group moves together, slowly, angling across and slightly downstream towards the exit.

A few details that make a difference:

• Keep boots on for grip and to protect your feet.
• Stow loose clothing like a flapping raincoat to cut drag.
• Undo the chest strap so you can get out of the pack if you need to, but keep the hip belt done up so the pack stays balanced.
• Clip your beacon to your body, not the pack, so you still have it if the pack goes.
• Shuffle, keeping feet wide and low rather than taking big steps.
• Agree on signals before you start, including the signal to turn back. You won’t hear each other over a loud river.

Turning back mid-river is the hardest part, which is why groups practise it on dry land first. The Mountain Safety Council describes a “caterpillar turn”, where one end of the line stays put as an anchor while the rest pivot around it.

Crossing with children

A crossing can be a good learning moment on a family trip, but it adds risk. Only consider it if there are enough adults with crossing skills to support each child, every child is comfortable, and the river is well within everyone’s limits. Practise the mutual support grip at home or in a shallow, slow stream first.

The habit to keep

The people who come home from river trips are rarely the ones with the best technique. They are the ones who planned to wait, carried the food and shelter to do it, and turned around early. Learn the skills properly through a Mountain Safety Council course or a club, and treat every crossing as optional.