Strong gale, storm and hurricane-force wind
In DMI's warnings it is the mean wind – the average wind speed over 10 minutes – that sets the level. Gusts can be much stronger, so a warning also mentions hurricane-force gusts when they are expected above 32.6 m/s.
| Warning | Mean wind | Level |
|---|---|---|
| Strong gale (stormende kuling) | over 20.8 m/s | Category 1 (yellow) |
| Storm | over 24.5 m/s | Category 2 (orange) |
| Hurricane force (orkan) | over 32.6 m/s | Category 3 (red) |
A wind warning can cover an area as small as a single municipality. DMI can issue an early warning up to five days ahead, while the warning itself comes at most 36 hours before the storm. The active warnings are on DMI weather warnings today.
Two kinds of storm warning
The Danish word stormvarsel is used for two different things. One is DMI's warnings for land and coast, described above. The other is the storm warning in DMI's sea-area forecasts for sailors, issued when a storm is expected at sea within the next day. If you sail, follow the sea-area forecasts.
High water and storm surges
When a storm pushes sea water towards the coast, the water level rises. DMI warns of high water (forhøjet vandstand) before it happens, and the limits differ from coast to coast:
| Coast | Category 1 | Category 2 | Category 3 |
|---|---|---|---|
| Inner Danish waters and the Baltic | 125–140 cm | 140–160 cm | over 160 cm |
| West coast of Jutland | 190–250 cm | 250–300 cm | over 300 cm |
| Wadden Sea | 240–300 cm | 300–400 cm | over 400 cm |
These are the limits as of October 2026. At the Skagerrak and in the Limfjord, DMI only warns from 130 cm. In a public consultation DMI has proposed raising the lowest limit for the Wadden Sea coast of Tønder Municipality from 240 to 325 cm, expected from November 2026.
The word stormflod (storm surge) has a special meaning in Denmark. Naturskaderådet, the natural hazards council (formerly Stormrådet), decides afterwards whether there was a storm surge on a given stretch of coast. A storm surge is declared when the water level is one that statistically occurs less often than once every 20 years, and the decision rests on a statement from the Danish Coastal Authority and DMI. Only then can you claim compensation from the storm surge scheme – no later than two months after the event, either in Naturskadebasen or through your insurer. Storm surges can hit Denmark from October to April.
Before the storm
- Remove or tie down loose things such as garden furniture, trampolines and building materials.
- Close doors and windows, and don't park close to tall buildings or under trees.
- Keep a torch, a battery radio and a charged phone or power bank ready in case the power goes.
- Check the moorings if you have a boat.
- If you live on the coast or in a low-lying area, find out where your municipality hands out sandbags.
During the storm
- Stay indoors. Don't go out to secure things or patch the roof while it's blowing.
- Keep away from forests and bridges, and don't go out to watch the storm.
- Postpone journeys if the authorities advise against travel.
- Only call 112 in an emergency, and only share information you know is correct.
When the water rises
- Cover low doors, basement shafts, floor drains and toilets with plywood, plastic or sandbags.
- Move animals and valuables to safety, and secure dinghies and boats.
- Don't park in harbour areas when DMI warns of high water.
- Don't drive or walk into flooded areas – turn back. Call 112 if you can't get to safety yourself.
- Be ready for power and heating to be cut for a while.
More generally, the Danish Agency for Societal Security (Styrelsen for Samfundssikkerhed) recommends that every household should be able to manage on its own for three days: 3 litres of water per person per day, food that keeps, necessary medicine and a radio that runs on batteries, solar power or a hand crank.
Storms and storm surges to remember
- 12–14 November 1872: the storm surge in the inner Danish waters killed about 250 people.
- 24 November 1981: the water reached 4.3 metres in Esbjerg harbour – the highest DMI has measured there.
- 5–6 December 2013, storm Bodil: Thorsminde measured a mean wind of 36.6 m/s and gusts of 44.2 m/s, and the water reached 2.95 metres above normal. Stormrådet later declared a storm surge in large parts of the country.
- 20–21 October 2023: the Baltic storm surge reached 216 centimetres above normal in Aabenraa. According to DMI, the Baltic had not seen higher water levels overall since New Year's Eve 1904.
Sources (in Danish)
- DMI: Varsler om farligt vejr i Danmark
- DMI: storm surges and historic storm surges
- DMI: Bodil and DMI on the 2023 storm surge
- Lex.dk: Storm
- Naturskaderådet: damage after a storm surge
- Police: extreme weather
- Danish Emergency Management Agency: hurricanes and strong storms and flooding from the sea
- Danish Agency for Societal Security: Prepared for crises
Advarselslisten is not an authority. Always follow the authorities' instructions, and call 112 if life is at risk.