Jean-Luc Demaret G
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Weather · Safety · Cancellation
Rain on the Semois: what should you do about kayaking?
Is rain forecast, or is there a flood or a drought? Stay calm. Here is how to tell 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. It is updated throughout the day.
La Semois
⛔ Closed
0.8 m³/s (range 2.2–50)
La Lesse
⛔ Closed
0.8 m³/s (range 1.5–52)
L'Ourthe
⛔ Closed
1.1 m³/s (range 2.5–65)
L'Amblève
⛔ Closed
0.7 m³/s (range 1–21)
Le Viroin
⛔ Closed
0.4 m³/s (range 1.6–23)
Le Bocq
✅ Open
0.9 m³/s (range 0.4–20)
⚠️ The Semois is currently closed, but other rivers remain navigable (see above). You can switch to one of them. The full detail is on each river dashboard.
Rain does not mean cancellation
This is the most persistent misconception: “it is raining, so the kayaking is cancelled”. That is wrong. You are on the water anyway, and wet in any case: 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 but the flow rate of the river.
The risk comes from heavy, prolonged rain, especially when it falls upstream in the catchment area. A few hours later the flow rises and can pass the maximum threshold. Conversely, an isolated storm on dry ground is often 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, because their catchment area, gradient and size differ. It therefore often happens that another river stays perfectly navigable on the same day. Rather than cancel, we can steer you towards the one that is open.
The "fallback river" reflex
- Semois in flood, Lesse or Ourthe navigable? Wider rivers like these sometimes cope better when the water rises. See the comparison of the rivers.
- All in flood? Wait. After the peak the flow often drops back within 24 to 48 hours, and free rescheduling is guaranteed.
- Level too low (drought)? Here the opposite applies: head 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. Just choose a river marked “open”.
Our cancellation & refund policy
Transparency is central to how we operate. You take no financial risk linked to the river conditions.
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Free cancellation
You can cancel free of charge up to 24 hours before departure, with no need to justify yourself.
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River non-navigable
If the river is closed on the day (flood or level too low), 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, so no large sum is 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, and not that you take risks to “make a booking pay off”.
Drought: when the level is too low
We think first of floods, but the other limit of navigability is drought. In 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, for your comfort as much as to protect the riverbed and its wildlife.
These episodes cluster 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 do not hesitate to aim for a river with a larger catchment area, which holds a better level in dry spells.
Apart from navigability, drought raises a question of environmental responsibility. When the level is low, the river warms up, its oxygen falls and its wildlife (fish, larvae, riverbed molluscs) becomes particularly vulnerable. Craft scraping over an almost dry bed cause lasting damage to these habitats. By suspending navigation below the minimum threshold, we protect the river as much as the comfort of the paddler. That is also why the thresholds are not negotiable: they express a balance between leisure 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, and this requirement 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 has no shortage 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, which is spectacular in the rain. Discover Bouillon.
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The Caves of Han
A grand underground site, fully sheltered from the weather and a short distance from the valley.
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Dinant & its citadel
A collegiate church, a citadel perched above the town and the banks of the Meuse. See Dinant.
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Local produce & gastronomy
Cheese dairies, Ardennes ham and Trappist beers: a rainy day suits a gourmet tour perfectly.
And of course, you can reschedule your descent to a day with a better flow. The Semois will always be there, and it is often even more beautiful after the rain.
Anticipating: read the weather AND the flow
To prepare an outing well, cross-check two complementary pieces of information. The weather tells you about comfort (temperature, wind, rain, sunshine) and about the coming trend: a run of rainy days in the forecast suggests the flow will rise. The measured flowfor its part gives you the reality of the moment, which alone decides navigability. Neither is enough without the other.
A few days ahead, watch the rainfall forecasts over the catchment area (and not only over the valley), because rain falling upstream, sometimes far away, is what swells the river. The day before, look at the flow trend: is it rising, stabilising or falling back? Finally, on the morning itself, 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 behind our flow forecasting algorithm applies for you.
The right gear when the weather is uncertain
In changeable weather, gear makes the difference between a fine adventure and a spoiled outing. Favour quick-drying clothing (synthetics, and above all no cotton, which stays cold and wet), bring a windproof layer since 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.
Do not forget sun protection: even under a grey sky, the glare off the water burns. Also protect anything that fears water (phone, keys, papers) in the barrel, or better still leave it in the car. The approved buoyancy aid, which is 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 removes the main reason people 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, because a river at the right level in the beautiful light after rain gives unforgettable descents.
Kayak weather through the seasons
Every season has its own weather and its own traps. In spring, the air warms up quickly but the water stays cold, and frequent rain sometimes keeps flows 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 golden rule of summer is to set off early (fewer people, cooler water during the hot hours) and to check the flow the day before a long weekend.
In autumn, the first rains refill the rivers and the valley takes on splendid colours, but the water cools noticeably and the wetsuit becomes useful again. Winter, finally, is reserved for seasoned, well-equipped paddlers: flows are often strong, the water icy and the days short. The logic does not change with the season: you watch the rainfall trend, then the flow of the day, and you adapt or you postpone. This simple discipline turns the weather, so often felt as a constraint, into an ally of a successful outing.
Frequently asked questions
Can you kayak when it rains?
Light rain does not stop navigation, because the flow is what counts. While it stays within the navigable range, the descent goes ahead. After heavy rain the flood flow can exceed the maximum threshold, and navigation is then prohibited as a safety measure.
What if the outing 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. The river conditions carry no financial risk for you.
What is your cancellation policy?
Free cancellation is possible up to 24 hours before departure. In dangerous conditions (flood, level too low) a refund or rescheduling is guaranteed. Booking online, you pay only a reduced platform fee (≈10%), and the balance is paid on site.
The Semois is closed but I still want to paddle: what can I do?
Another river (Lesse, Ourthe, Amblève) may stay navigable while 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 becomes too low and navigation is suspended. Check the flow of the day before you set off.
Book with peace of mind
Free cancellation, and a guaranteed refund if the river is closed. Check the flow, then go for it.
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