Never ever again unprepared for Nevera, 16 June, Šibenik

I thought we were familiar with most of the winds that sweep across the northern Adriatic, but last night we were caught off guard by a Nevera — one of those sudden Adriatic storms that strike without warning and vanish just as quickly. In less than two hours, over 30 boats were driven ashore, and rescue services were responding to incidents all along the northern coastline of Croatia.

Picture south of Rovinj by A. Simunović

Let me tell you what happened to us...

By 22:00, a couple of hours after it hit Rovinj, a similar local storm formed around Šibenik and took us completely by surprise. The forecast for the day had been uneventful, predicting the usual Maestral—a northwesterly afternoon wind that gradually strengthens until around 19:00, then fades to a gentle breeze through the night and into the following morning. This pattern had held steady for the past eight days as we explored the Kornati islands.

The Nevera is a sudden and intense storm wind that occurs along the Croatian Adriatic coast, particularly during the warmer months. Unlike the more predictable Bora or Jugo winds, the Nevera is associated with rapid weather changes and thunderstorms. It typically forms when hot, humid air from the land collides with cooler, unstable air masses over the sea. This convergence leads to the formation of cumulonimbus clouds, often resulting in short but violent squalls accompanied by lightning, heavy rain, and abrupt wind shifts. The Nevera often arises with little warning, making it particularly dangerous for maritime activities.

The impact of the Nevera can be significant, especially for sailors, beachgoers, and small coastal communities. Sudden wind gusts can capsize boats, damage coastal infrastructure, and pose serious safety risks to swimmers and hikers. While the storms are usually brief, they can lead to localized flooding, fallen trees, and electrical outages. Mariners are strongly advised to monitor weather forecasts closely and heed local warnings, as the Nevera can strike within minutes and with great force. 

Watch this video if you would like to see the devastating effect of Nevera.

We might have seen it coming, had we paid closer attention to the heavy clouds building in the western sector that afternoon—growing in size and form into towering cumulonimbus, with increasingly frequent lightning. But at the time, we were securely moored to the town quay in Šibenik, enjoying a light breeze. Then, at 22:30, everything changed in a matter of seconds: the wind surged to 20 m/s (around 40 knots), violently unfurling the Code 0 sail that was still hoisted on the bowsprit.

I jumped out and tried in vain to furl it back in. With no time to put on gloves or even get dressed, I made the decision to drop the sail as quickly as possible while the wind howled around us. Under the strain, the boat began drifting sideways, pressing against neighboring boats, and one of our stern mooring lines even tore a cleat clean out of the dock. Fortunately, once the Code 0 hit the water, the boat stabilized. I was able to gradually haul the sail back on board and resecure the stern line to another cleat. Within 20 minutes, the storm had passed and calm returned—leaving only the state of my hands as a reminder.

Burnt marks on hands caused by releasing the spinnaker halyard in emergency

A few pictures in the newspaper the day after:

Lessons learned:

• Watch at least morning and evening the weather forecast
• Not just on Windy of other general sites, but on local weather sites:
• Croatian Meteorological and Hydrological Service
• Bora Adriatic Marine Forecast
• Croatia - Weather at the Adriatic
• Weather forecast for the Adriatic sea
• In case of doubt about the weather at an anchorage, be ready to depart rapidly:
• Remove furled spinnaker,
• Secure the furled genoa and trinquette,
• Stay away from the shore
• Double the length of the chain
• Start the engine forward to decrease the pullk on the anchor