Storm formation: Stormy conditions lasting several days in the North Sea and the Baltic Sea

A stormy Friday, an even stormier weekend

On Thursday, 22 October 2026, storm ‘Austen’ is expected to intensify rapidly over the Atlantic and move towards the North Sea on Friday. The the British Met Office expects a drop in pressure of at least 24 hectopascals within 24 hours and, consequently, the rapid development of a low-pressure system, also known as bombogenesis.

Gale-force winds are forecast for the Dutch and German coasts, with the Dutch Meteorological Institute estimating that their path and intensity will be Royal Netherlands Meteorological Institute (KNMI) are still uncertain.

The Baltic Sea, too, will come under the influence of the series of low-pressure systems with a time lag. Winds there are likely to pick up initially, particularly in the western Baltic Sea, and later further east as well.

Another powerful low-pressure system is expected to follow at the weekend. The German Weather Service Gale-force winds are once again expected on Saturday along parts of the North Sea coast, with gusts on Fehmarn and gale-force winds at Cape Arkona. This may result in short, steep waves, particularly in the western Baltic Sea, around Fehmarn and in the Danish straits.

The weekend low-pressure system is encountering seas that are already rough; so far, there are no signs of a prolonged lull between the two systems. This applies not only to the North Sea: crews on transhipment voyages across the Baltic Sea must also expect increasingly difficult conditions. Whether unusually high or low water levels occur there will depend on the actual track of the low-pressure system and the resulting wind direction.

Not unusual for the end of October

A severe North Sea storm at the end of October is not unusually early. The North Atlantic is already in its autumn storm season at this time of year. Increasing temperature differences between the northern and southern air masses, combined with a strong jet stream, encourage the formation and rapid intensification of low-pressure systems. Almost to the day, a storm system also heralded the arrival of autumn on the coasts last year.

What is unusual, however, is the possible combination of a rapid drop in pressure and several low-pressure systems in quick succession. For sailors, the weather conditions coincide with a particularly unfavourable transitional period: some yachts are still on their transit voyages, whilst others have to make it to a previously agreed crane-out appointment. At the same time, many boats are already in winter storage.

Postpone transfers and jib extension dates

Anyone still safely moored in harbour should postpone any planned transfer across the North Sea or the Baltic Sea. A fixed crane appointment is no reason to set sail during an uncertain weather window. Crane operators and shipyards should be informed as early as possible.

It is not just the conditions at the start that are crucial. The wind, waves and tide at the most challenging section of the route, as well as during the subsequent entry into harbour, are the decisive factors. Cold water, short days, rain, poor visibility and rough seas further deplete the reserves of the vessel and its crew.

Seegatten is no longer open to traffic

The straits between the Dutch, East Frisian and North Frisian islands should not be navigated in such weather conditions. Even at five to six on the Beaufort scale, dangerous ground swells can form over the shoals that extend far out to sea – even without a headwind and in places where a crew may still believe they are in deep water. If the tidal current runs against the wind and the swell, the waves become even shorter, steeper and more breaking.

The Elbe estuary can also become extremely hazardous in strong westerly to north-westerly winds, with an ebb current running out and heavy commercial traffic. Those already in the German Bight may, depending on their position, the wind and the state of the sea, consider Heligoland or the Jade as alternative destinations. The North-East Harbour on Heligoland can be entered without prior notification; visiting vessels must report to the harbour master after mooring. In the Jade, the sheltered outer harbour at Hooksiel may be an option. However, the decision must be made well in advance whilst still out in deep water. A strait is not an escape route when the sea is rough. (wsc-helgoland.de)

Inland routes as an alternative

In the Netherlands, the Staande Mastroute can, in principle, offer an alternative to travelling along the open North Sea coast. However, it will not be fully open to traffic in 2026r. Both the western and eastern routes through North and South Holland are closed. There are also restrictions in the northern Netherlands. The Dutch sailing website “Do as you are told“shows the current closures on an overview map. Crews should check the entire route, including bridge opening times and lock operations, before diverting to inland waterways.”

In Germany, the Kiel Canal can be a sheltered alternative. The Elbe-Lübeck Canal is only suitable for most sailing yachts with the mast lowered, due to the limited clearance under the bridges. Whilst inland routes offer protection from heavy seas, they do not protect against gusts of wind, falling branches or short-term restrictions at bridges and locks.

On land or in the water: securing boats

Yachts that are still moored in the harbour or overwintering there should be storm-proofed in good time and whilst it is still light. Sails, particularly furling sails, present a large surface area to the wind and should be furled down where possible. Tarpaulins, galley tents and bimini tops should also be removed from the boat or secured more securely.

Mooring lines should be checked for wear and chafing; they should be doubled where necessary and run as long as possible. Additional spring lines and suitable shock absorbers help to reduce peak loads. At the same time, there must be sufficient scope to allow for possible changes in water levels. The forces should be distributed across several sufficiently sturdy cleats. Where possible, the lines should be secured in such a way that the harbour master or assistants can adjust them from the jetty.

Fenders must be fitted at the points of contact that are actually at risk and must not slip under the jetty when the boat heels or the water level changes. Loose equipment must be stowed below deck, and hatches and lockers must be kept closed. Anyone who is unable to get to the boat themselves should ask the harbour master or a trusted person to carry out a check.

Check the boats at the external storage site

Even yachts that have already been uncraned should to be checked once more before the storm. The storage stand must be placed on firm ground and support the boat at points on the hull that can bear the load. After prolonged rain, soft ground may settle and cause a support to sink. Supports that are extended a long way out should be secured against one another; some winter storage facilities also lash the trestles to ground anchors to prevent them from tipping over and causing a domino effect.

Yachts with a standing mast require particular attention. Sails must be fully furled, including the furling mainsail and furling jib. Flapping halyards and strong vibrations in the rig should be avoided as far as possible. However, the rig should not be rigidly braced to a point on the ground using a halyard, as this can cause additional stress.

Large, loose tarpaulins increase the wind load. They must be taut and must not be secured to wooden blocks or wedges that could be pulled out by the movement of the tarpaulin. It is therefore advisable to carry out your own checks, even at professionally run winter storage facilities.

Water level trends still uncertain

Whether a storm surge occurs in the North Sea and how water levels in the Baltic Sea develop will depend on the track, wind direction and duration of the weekend low-pressure system. A particularly decisive factor is whether a prolonged westerly to north-westerly wind sets in after the low-pressure system has passed.

The current BSH forecast for the Baltic Sea does not yet cover the critical period. Only moderate deviations are expected there until Thursday. This does not yet mean the all-clear has been given for the weekend. Boat owners should updated water levels- and therefore check storm surge forecasts daily.

Further articles on the subject of storms and bridge crossings

Storm in the harbour: How to secure your yacht explains how to prepare mooring lines, fenders and equipment.

Outdoor winter storage: what you need to bear in mind deals with onshore storage and the additional stresses placed on the mast when it is upright.

The NOK Guide for Sailors helps with the preparation of a canal linking the North Sea and the Baltic Sea.

Have you postponed a transfer or a crane operation due to the storm forecast? What precautions are you now taking at the port or at your external storage facility? Share your experiences in the comments.