Jean-Luc Demaret G
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Weather · Safety · Cancellation
Kayaking on the Semois in the rain: what to do?
Rain forecast, flood, drought? Don't panic. Here is how to know whether the river is navigable today, what our cancellation policy provides, and which river to turn to if the Semois is closed.
Today, where can you paddle?
River status in real time, computed from the flow measured at the SPW stations and the official navigability thresholds. Updated throughout the day.
La Semois
✅ Open
6.9 m³/s (range 2.2–50)
La Lesse
✅ Open
4.9 m³/s (range 1.5–52)
L'Ourthe
✅ Open
6.1 m³/s (range 2.5–65)
L'Amblève
⛔ Closed
5.6 m³/s (range 2.5–44)
Le Viroin
✅ Open
1.6 m³/s (range 1.6–23)
Le Bocq
✅ Open
1.4 m³/s (range 0.4–20)
👍 The Semois is navigable right now. Still check the flow just before setting off, especially after recent rain. The full detail is on each river dashboard.
Rain does not mean cancellation
It is the most persistent misconception: "it's raining, so the kayaking is cancelled". Wrong. You are already on the water, and wet anyway: light rain changes nothing about safety, and paddling through a fine drizzle in a misty valley even has something magical about it. What really decides navigation is not the sky, it is the flow rate of the river.
The risk comes from heavy, prolonged rain, especially if it falls upstream in the catchment area: a few hours later, the flow rises and can cross the maximum threshold. Conversely, an isolated storm on dry ground will often be absorbed without major consequences. That is why we never reason "by the weather" but "by the measured flow", the only reliable data. To understand the thresholds in detail, see our table of navigable flow rates.
If the Semois is closed: the alternatives
Here is the great advantage of operating on several rivers. When the Semois is in flood, its neighbours do not all react in the same way: their catchment area, their gradient and their size differ. It therefore happens frequently that another river stays perfectly navigable on the same day. Rather than cancelling, we can steer you towards the one that is open.
The "fallback river" reflex
- Semois in flood, Lesse or Ourthe navigable? These wider rivers sometimes cope better with a rise in water. See the comparison of the rivers.
- All in flood? Wait: after the peak, the flow often drops back within 24 to 48 hours. Free rescheduling is guaranteed.
- Level too low (drought)? Here it is the opposite: aim for the rivers with the most sustained flow, or wait for the next rain.
The "Today, where can you paddle?" block at the top of this page does this work for you, live: simply choose a river marked "open".
Our cancellation & refund policy
Transparency is at the heart of how we operate. You take no financial risk linked to the river conditions.
🕒
Free cancellation
You can cancel free of charge up to 24 hours before departure, with no need to justify yourself.
🌊
River non-navigable
If the river is closed (flood or level too low) on the day, your outing is refunded or rescheduled free of charge, automatically.
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Transparent payment
Online, you pay only a reduced platform fee (around 10%). The balance is paid on site: no large sum tied up.
In short: the weather and the state of the river are never at your expense. Our interest, like yours, is that you paddle in good conditions — not that you take risks to "make a booking pay off".
Drought: when the level is too low
We think above all of floods, but the other limit of navigability is drought. During a hot, dry summer, the flow can drop below the minimum threshold: the river becomes too low, the rocky bed shows through, craft scrape and some passages become impassable. Navigation is then suspended, as much for your comfort as to protect the riverbed and its wildlife.
These episodes concentrate in July and August and can last several weeks. Here again, the data of the day prevails: a river judged "too low" last week can become navigable again after a good downpour. Watch the flow, and don't hesitate to aim for a river with a larger catchment area, which keeps a better level during dry spells.
Beyond navigability, drought raises a question of environmental responsibility. When the level is low, the river warms up, its oxygen drops and its wildlife (fish, larvae, riverbed molluscs) becomes particularly vulnerable. Scraping craft over an almost dry bed causes lasting damage to these habitats. By suspending navigation below the minimum threshold, we therefore protect the river as much as the comfort of the paddler. This is also why the thresholds are not negotiable: they express a balance between leisure activity and the preservation of a listed natural heritage, often within a Natura 2000 zone. Paddling at the right moment also means respecting the river that welcomes us — a requirement that is an integral part of our approach.
Plan B: what to do when it really rains
If the river is genuinely closed and you are on site, the Ardennes is not short of indoor activities or things to do under a grey sky to save the day. The Semois valley and its surroundings are full of memorable visits:
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Bouillon Castle
The oldest medieval fortress in Belgium, spectacular in the rain. Discover Bouillon.
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The Caves of Han
A grand underground site, fully sheltered from the weather, a short distance from the valley.
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Local produce & gastronomy
Cheese dairies, Ardennes ham, Trappist beers: a rainy day is perfect for a gourmet tour.
And of course, you can reschedule your descent to a day with a better flow: the Semois will always be there, often even more beautiful after the rain.
Anticipating: reading the weather AND the flow
Preparing an outing well means cross-checking two complementary pieces of information. The weather tells you about comfort (temperature, wind, rain, sunshine) and the coming trend: a run of forecast rainy days suggests a rise in the flow. The measured flow, for its part, gives you the reality of the moment, the only thing that decides navigability. One without the other is not enough.
A few days ahead, watch the rainfall forecasts over the catchment area (and not only over the valley): it is the rain falling upstream, sometimes far away, that swells the river. The day before, look at the flow trend: is it rising, stabilising, falling back? On the very morning, finally, check the value of the day on your river's dashboard. This three-stage routine — catchment, trend, value of the day — avoids almost every nasty surprise, and it is exactly the logic that our flow forecasting algorithm applies for you.
The right gear when the weather is uncertain
In changeable weather, it is the gear that makes the difference between a fine adventure and a spoiled outing. Favour quick-drying clothing (synthetics, above all no cotton, which stays cold and wet), bring a windproof layer because wind chill is felt as soon as you are damp, and slip a dry change of clothes into the watertight barrel provided. In cool water, the neoprene wetsuit becomes a real asset: see our page dedicated to water temperature and gear.
Don't forget sun protection: even under a grey sky, the glare off the water burns. And think about protecting anything that fears water (phone, keys, papers) in the barrel or, better, leave it in the car. The approved buoyancy aid, provided and compulsory, is worn snug at all times, whatever the weather: it is the piece of gear that saves lives.
Safety first: our commitment
Behind every "open" or "closed" status shown on this page lies a simple conviction: no descent is worth an unnecessary risk. We would rather close a river one day too many than let a group set off in doubtful conditions. That is why our cancellation policy is so protective: by removing any financial stake, it takes away the main reason that pushes people to paddle when they should not.
This requirement is built on official data (SPW stations), a real-time monitoring algorithm and the field expertise of Quentin Deligne, a specialist in navigation in the Belgian Ardennes. When in doubt, the instruction is always the same: we postpone. The Semois valley rewards patience — a river at the right level, in beautiful after-rain light, offers unforgettable descents.
Kayak weather through the seasons
Each season has its weather and its traps. In spring, the air warms up quickly but the water stays cold and the frequent rain keeps flows sometimes high: this is the period of fine water levels, provided you are well equipped and watch for rapid rises after showers. In summer, the risk reverses: storms can cause localised flash floods, while long dry spells lower the level until some rivers close. The summer golden rule: set off early (fewer people, cooler water during the hot hours) and check the flow the day before a long weekend.
In autumn, the first rains refill the rivers and the valley dresses in splendid colours, but the water cools noticeably: the wetsuit becomes useful again. Winter, finally, is reserved for seasoned and well-equipped paddlers: often strong flows, icy water, short days. Whatever the season, the logic does not change: you watch the rainfall trend, then the flow of the day, and you adapt — or you postpone. It is this simple discipline that turns the weather, often experienced as a constraint, into the ally of a successful outing.
Frequently asked questions
Can you kayak when it rains?
Light rain does not prevent navigation: it is the flow that counts. As long as it stays within the navigable range, the descent goes ahead. After heavy rain, the flood flow can exceed the maximum threshold: navigation is then prohibited as a safety measure.
What happens if it is cancelled because of the weather?
If the river is non-navigable on the day of your booking, you are refunded in full or rescheduled free of charge. No financial risk linked to the river conditions.
What is your cancellation policy?
Free cancellation up to 24 hours before departure. Dangerous conditions (flood, level too low): refund or rescheduling guaranteed. Online, only a reduced platform fee (≈10%) is paid, with the balance on site.
What can I do if the Semois is closed but I still want to paddle?
Another river (Lesse, Ourthe, Amblève) may stay navigable when the Semois is in flood. Check the real-time statuses at the top of this page to switch to an open river.
Can you kayak during a drought?
Not always: in a very dry summer, the flow can drop below the minimum threshold. The river then becomes too low and navigation is suspended. Check the flow of the day before you set off.
Book with peace of mind
Free cancellation, refund guaranteed if the river is closed. Check the flow, then go for it.
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