The ultimate forecast is a grunty Norwester, warm and wet, slamming into the Southern Alps, getting an oreographic super charge and  saturating the valleys with an unfathomable volume of water, clean, pure water. Give this time to sink into the rivers, then, just as it swings to the south, the hose gets turned off the sun comes out, and we are poised, ready to paddle some of the best white water in the country. With the wonders of online weather forecasting, and a bit of intuition, we can nearly always get it right.

There is a touch of stigma in paddling flooded rivers, “flooded rivers are dangerous”.

Rivers in general are dangerous, as are mountains. Irrespective of how much water is in a river, rocks, water and gravity behave in a predictable manner. As a generalisation, flooded rivers are faster, features are bigger and rapids are generally longer, relative to their usual flow. Take a rapid on a flooded small river and you’ll likely find a similar rapid on a normal flow big river.

So, like any back country user, we watch the weather and wait for the right conditions. The red on the rain forecast model normally prompts a few folk wriggling out of work and coordinating a meeting time.

Akin to making an assessment on avalanche conditions prior to going into the mountains, we monitor the weather closely looking for the right ingredients to get the ‘freshies’.. safely. How the precipitation falls, where its falls, when it fell. These all help create a picture of what the terrain will be like, and how it will change throughout the day.

One of our best rainy day activities is kayaking the gorgeous Lower Kakapotahi. A little known gorge 40 km south of Hokitika. Also known as the ‘little Waitaha” after her better known big sister running parallel to the south.

Granite plutons sitting west of the Southern Alps create distinct river corridors. Stubborn granite domes do not yield to the big floods. Geological weaknesses funnel water into fissures concentrating the erosive power. Rocks get polished over a millennia leaving architecture a skate park designer would be proud of

Unlike the geology of rivers flowing through the Southern Alps, granite river beds like the Kakapotahi tend not to change much.  Rocks become familiar. Layered with a given flow, we remember all the rapids and many of the features. As flow increases, a rock becomes a recirculating hydraulic, becomes a wave, becomes a BIG wave, becomes gone. At the upper end of the flow range, this familiarity becomes essential as the speed of our descent increases.  The river feels bigger, more powerful; being in the right place and knowing where that is keeps you in control.

Strangely, the heaviest rain is often nocturnal on the west coast meaning the best white water is at dawn. Families still sleeping, we slip out the door in the dark hopeful to have read the weather right. If you live on the West Coast you really need to appreciate rain, here, it is about as good as it gets!

From the put in, the Kakapotahi descends into a world largely untouched by people. Old growth rain forest clings to the valley walls, thousands of years in the making, protected by the steep terrain. Rain clearly nourishes this valley, the forest comes alive. Noise, colour, feel, to me, this environment in this weather embodies all that is ‘West Coast’. It could not be wetter. It the trip  goes well, we’ll be home for lunch, get it wrong and suddenly we are in a remote and inhospitable world days from civilisation.

The put in itself is the first challenge.  Slithering down a steep, muddy old moraine “trail”.  Kayaks are put on “leashes” so they don’t career down the hill and decapitate our comrades.  A knotted fixed rope assists the sketchiest section. 

A familiar marker rock indicates volume and trend, the higher it is, the more ‘full on’ it is, although some rapids get easier. The brown colour can be intimidating, but often is more related to the stability of upstream slips. Sometimes we run the shuttle first to let it drop a little more, sometime we berate each other for arriving too late, missing the ‘sweet flow’. We always talk, no egos, nothing to prove, all opinions valid. Today, its good to go.

The man they call “JV” sussing out the water level…

Early on in the journey, bedrock pinches the river into a four metre wide slot. Water thunders through a thin hall way framed by looming granite walls. It’s always intimidating floating up to this ominous spot. We take out on river right to scout the gorge. The gorge hasn’t been on for a few years since a 500 year old rimu tree became wedged sideways blocking the path of anything floating on the surface. A recent flood beat the log into submission, (a testament to the force of water),  today the gorge is back on.  Heart rates rise, grins form. A well-worn track leads to an outstanding vantage point. Perched 50 metres directly above the bowels of the chundering rapid, this birds eye view is a seldom offered perspective on the up-coming white water. Left, centre or right line, all completely different routes and with variable flows, this single rapid offers countless opportunities to test one’s white water prowess. Translating this helicopter perspective to a river level one requires conscious recalibration.

Regardless of the flow, the rapid is a tricky Class 5. The portage always an option (unless you’re here way too high in which case a small creek crossing might encourage a long sit contemplating your weather reading abilities). The gorge entrance is a little chaotic as 40 meters wide becomes instantly four. So long as you stay upright, you’re fine, as the smooth featureless walls cause no trouble. The water immediately flattens to a pool above a noteworthy  horizon line. Very much the point of no return. By now the decision has been made… Left line.

Float the flat water towards the horizon, centre left, suck in the O2 and calm the nerves. Spot the rock shelf with water running over it, when the time is right, accelerate with all you’ve got, aim more left knowing the water will carry you right (like shooting with a cross wind). Time your last stroke to be you best.

If you nail it, your kayak slides over the rock shelf with enough depth of water not to slow your momentum, hopefully your last stroke caught deep green water giving you the punch you need. You fly forward…for a split second you float mid-air, its calm, metaphorically quiet despite the a world of chaotic white way below you. Take the nano second to spot your landing. land flat is the goal, this keeps the kayak on top of the water and you in a position to have control.

Get this line wrong and your hull grinds on the rock shelf, momentum, is lost, you nose dive,  your kayak goes deep, appreciating a softer landing, but losing valuable seconds as you fight to resurface and get that control back.  Move centre so you have space to drive back right across falling water and into a surging eddy… Breath.

Same rapid, different line, less water… Paddler is Brian Urmson, photo by Barney Young.

For safety we run the gorge in pairs, we are each other’s safety net. From the surging eddy above, you can climb out of your kayak and clamber up to a rear flat spot. Here you can offer throw bag support to your team in the likely trouble spots and have immediate access to a log jam, that has never, but could, cause problems. This is the only spot where you can see your entire team. Those fidgeting at the top, those in the thick of it, and those on safety at the bottom.  We function as a team despite our physical separation.  Sign language controls the pace and gives additional beta that helps your mates nail the line.

If you’re not feeling it, now is the time to walk out. The final egress before descending into no man’s land. What awaits is near continuous Class 4  white water. As classy as it gets. Hopefully the river is high and dropping, but there’s a good chance of some latent down pours – the type that wind shield wipers can’t keep up with. This place comes alive in the rain, the uniqueness in seeing this environment in its saturated state is not lost on me.  From our dry suit cocoons, we comfortably get to experience an atmosphere most would seek shelter from.

Other than stopping to play on some surf waves or repeating a few of the favourite moves, we run this section fairly continuously. There is enough room and enough options for a big team to all be weaving through the same rapid at the same time, we all take the approach of keeping eyes on the paddler above us and paddler below us, which ensures everyone is always accounted for.

We fly through this scenic hydro slide, being thrown around as jets of water take hold of our buoyant boats, over, under and through waves, slamming into liquid crash pads, grinning like fools.

At the take out, the farmer pulls over, frowning, shaking his head, wondering what manner of creature has entered his domain. Helmets come off and faces get recognised, kids taught, sheds built, sheep sold, referrals made. In a heart beat, we go from freaks, to members of the same community. Conversation bounces from TB testing to ‘kayak design’ to local politics. He leaves still shaking his head… but I’m sitting next to him, soaking his seat and getting a lift back to the put in and our  car.

Paddling flooded rivers is not without its risks, we know this and do all we can to keep it as safe as possible. Mostly it’s about making good decisions based on good information, being with good people, and being in tune with your own ability. In getting this right, we take the worst forecast and turn it into the brightest day.

Kieth Riley is based in Hokitika, and has had a long career of pioneering hard whitewater, including the first full descent of the Waitaha.

He’s active in river conservation, and works as a rock and mountain instructor.