SAILING INTO A SERIES OF THUNDERSTORMS, AUGUST 2022

A derecho is forming and we have nowhere to go.

We are sailing into a series of downburst clusters on the 17./ 18. Aug. 2022. A very rare 1.000-mile-wide derecho is forming over the Mediterranean Sea, and we are getting sucked right in.

Thunderstorms are forming on the 17th of August over the Balearic Islands and stretching 1.000 miles (about 1.600 km) across the northern Meds to Mainland Italy and far into the inland, all the way up to Austria. Leaving in its path, a dozenth persons dead, large destruction of property, hundred damaged boats, and multiple sunken and stranded yachts.

Now in the aftermath, back in the safety of a marina, we trying to find out what exactly happened, in our crossing from Sardinia to Menorca, on the days of 16./17./18./19. August 2022, in what kind of weather system we ended up, and if there would have been a way to avoid this event.

Sailing into two thunderstorms on the coasts of Menorca & Mallorca. 17. & 18. August 2022

But what is a derecho exactly? Here is the explanation we have found online. Meteorologists' definition of a derecho is this:  

A derecho is a widespread, long-lived wind storm. A band of rapidly moving thunderstorms, variously known as bow echoes, squall lines, or quasi-linear convective system.

An event can be classified as a derecho, if the swath of wind damage extends at least 400 miles (about 650 km), is 60 miles (about 100 km) wide, includes wind gusts of at least 58 mph (93 km/h) along most of its lengths, and also includes several well separated 75 mph (121 km/h) or greater gusts.

Derechos can produce destruction similar to that of a tornado, but typically in one direction along a relatively straight path. Sometimes the term „straight-line wind damage“ is used to describe the damage a derecho event.

A typical derecho consists of numerous downburst clusters. A family of downburst clusters, that are, in turn, composed of many smaller downbursts, microbursts, and burst swaths.

Therefore derecho winds are the product of what meteorologists call downbursts.

Convective downdrafts, which comprise downbursts, form, when air is cooled by evaporation, melting, and/or sublimation (the direct change to vapor phase) of precipitation, in thunderstorms or other convective clouds. Because the chilled air is denser than its surroundings, it becomes negatively buoyant and accelerates down toward the ground.

Derechos occur, when meteorological conditions support the repeated production of downbursts, within the same general area. The "downburst clusters" that arise in such situations may attain overall lengths of up to 50 or 60 miles (80 to 100 kilometers) and persist for several tens of minutes.

Within individual downbursts there sometimes exist smaller pockets of intense winds called microbursts. Microbursts occur on scales (approximately 2 1/2 miles or 4 km) that are very hazardous. Still smaller areas of extreme wind within microbursts are called burst swaths. Burst swaths range from about 50 to 150 yards (45 to 140 meters) in length. The damage they produce may resemble that caused by a tornado.

Experts say the events from the 18th August-storm, pass those requirements, although it is very rare for the region. It originated on the Balearic Islands before sweeping across the Mediterranean and into Europe. In this wide-reaching event, some of the gusts that were measured over the island of Corsica, were hitting 225 km/h (140 mph).

According to the French maritime authority, in Corsica more than 100 wrecked or stranded ships had called for emergency help, as a result of the sudden, extreme, violent, and entirely unpredictable weather event. Two bodies, who had died on the water as a result of the storm, were found on the West and the East coasts by the rescue crews.

Pleasure boats had capsized or been thrown adrift, and at one point 350 people had been reported missing, but luckily had been found alive and well later. In the end, at least five people were killed, in and around the French Island alone, in total, according to the Associated Press.

We left on the Aug 16th from the Porto Conte anchorage on the northwest side Island of Sardinia towards Menorca.

Our plan was to sail first to one of the anchorages on the east side of Menorca. A two-day trip. There we would spend some time on the Balearic Island of Menorca before heading further west to Barcelona. The forecast for the 16th was light and variable wind in the morning than was predicted to increase in the evening and night. In reality, we had run under motor, all day and all night.

The next morning 17th in the middle between the two islands Sardinia and Menorca, we started to be getting wind. But not from the direction as forecasted. During the day the wind got stronger and ended up between 20 - 25kt+. At the end of the day, we sailed with the wind coming from behind, with a triple reefed mainsail.

All afternoon of the 17th., the VHF radio was prod-casting warnings of a gale, with strong wind, developing thunderstorms. Location: Balearic Islands, Sardinia, Mainland Spain, Sicily, Corsica, and the French coast. Basically all over the place, leaving us nowhere to go, if we were looking for shelter.

By the end of the day, we were close to Menorca when we realise that the whole Island was covered in a large dark, and frighting weather front. We made the decision to stay clear of the Island and sailed away from the weather front towards the island of Mallorca.

Before nightfall, we decided to change the sail configuration, from the triple reefed mainsail to a much easier-to-handle staysail, if the wind would come up even more. One hour after changing the sail configuration a very heavy downburst was hitting us, coming in at us in seconds, with left us no time to react. Luckily we had the right sail up and no damage was done. The storm front from Menorca had got up with us. After about 10 min. craziness, with extreme wind, the condition was back to 20 - 25+ knots, thru the night into the morning.

In the morning for a period, we had a clear sky, with strong winds. We were making good progress towards Mallorca. Everything looked good and we thought, we had left the weather system behind, only to find out another system is waiting for us on the northeast side of Mallorca. And the system is sucking us right in.

Over Mallorca, another big storm front had developed. The cloud formation looked frightening. Not much later, in the early morning hours of the 18th Aug., we were hit by an even more powerful down-burst than the one before on Menorca. The down-burst we experienced this time was very extreme.

Luckily Florence May is a strong boat and was prepared for this kind of event. All the rigging is new, the running rigging is in good shape, and all the working systems are permanently worked on, so she could handle the condition without bigger problems. When the gust hit us, Florence May was pushed over to the side, by the wind, to a 35+ degree tilt, where she would stay for the lengths of the event, with only a portion of the staysail out, for steerage.

In the end, the journey thru this chain of events ended after 3 days on the southeast side of Mallorca where the weather finally cleared and we made the decision to keep on sailing for another day towards the Islands Formentera & Ibiza.


Conclusion: None of the big weather stations had forecasted this event. The forecast of a derecho remains one of the most challenging tasks for any operational meteorologist today.

Experts believe the warm water temperatures of the mediterranean sea, with record numbers, have fueled this weather system. The Meds have seen a record water temperature rise of 5 °C higher than average in some areas.

Weather warnings were coming to late for us, with nowhere to go for shelter.


This should have warned us: Looking back at the forecast, the day we left, 16th August, was not a good day to leave Sardinia. No weather system had settled yet. Therefore we could not foresee any abnormalities in the weather.

A conversation we overheard on the VFH Radio, between two yachts leaving Sardinia on the 17th of August, how were wondering about the weather pattern, which had much stronger wind and was coming from a different direction than their forecast models, did make the decision, to turn back to Sardinia, and wait little longer for departure. They had the feeling, that because the weather forecast did not match the weather conditions out there, in reality, is totally wrong, something is maybe going on.

Moisture. Water temperatures play a role in how much moisture is available in the atmosphere. In reduced terms, a derecho system consists of a line of downstream-replicating, ordinary thunderstorms. There are three basic ingredients needed for thunderstorm development: moisture, an unstable atmosphere, and some way to start the atmosphere moving. The moisture acts as fuel when combined with warmth.

We had already one day before our departure on the 16th, a high level of moisture, together with the high temperature in August, and the undeveloped weather system at the time, warning signs should have been up, for developing thunderstorms.

One day after our departure, on the 17th, the moisture on the boat was incredibly high. It felt like sitting in a Turkish steam bath. This high level of moisture in the air we only know from the tropics, where heavy rain, high temperature, and sunshine, exchange in short intervals.

We believe the wind relatively strong wind that we experienced throughout all day of the 17th., was basically created by the atmosphere getting sucked in by the forming thunderstorms.

At the end of the day, this extreme weather event had developed and started.


Lucky for us: Luckily we were out at sea, and not in one of the anchorages when we got hit by the downbursts. Lots of boats were lost, because their anchor lost its grip and motoring against the wind was not possible.

Good, we were on the lee-shore. We had no danger of hitting land for hundreds of sea-miles. Turning away from the system, was a lucky move, and just timed right.

And finally, we had the right sails up when the gusts hit us, and we have a very strong boat that was prepared for an event like this.


Extreme weather events today: There can be no more denying, global heating is supercharging today's weather. Analysts are clear about this. The likelihood of extreme weather across the planet, due to climate change is accelerating fast. Many weather events are now more severe, and are more often, taken part in different parts of the world.

New and rare weather patterns and events are very hard to predict. Meteorologists have to deal with new weather patterns and models not happened before, or are now being seen in new areas of the world. Therefore an accurate forecast of such a weather event is the most challenging task an operational meteorologist is facing today, and we will not count on it.

Our take on this is.  We will try to read the sign of the weather that is giving us a little better in the future when planning a trip. But in reality, it will be difficult to avoid something like this from happening again. So one thing is for certain. We will make sure the boat is always in good shape and prepared for any weather that is coming at us.

Courtesy: ESSL, European Severe Storms Laboratory; NOAA-NWS-NCEP Storm Prediction Center; EUMETSAT; E.U. Copernicus Marine Service Information; European Space Agency

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