Sea state, swell and glare on the north Minch

A watcher on a north Minch headland reads the water before reading the horizon. Sea state decides the first question: whether a back or a blow can be held long enough to name. Swell decides the second: whether anything shows at all above a moving surface. Glare decides the third, and it is the one most often ignored. Anyone weighing a long journey south, and asking about the beste reisezeit suedafrika safari, will recognise the same discipline: the season is not a date but a set of conditions.

Which months bring which species past the headland?

The north Minch is a channel, not an open ocean, and what passes is seasonal. Harbour porpoise are recorded in every month, though they are hardest to see in the flat calm of high summer, when a small back barely disturbs the surface. Bottlenose dolphin sightings cluster in the warmer half of the year, with a peak that shore records place between June and September. White beaked dolphin arrive with the feeding season, most often from July into September. Minke whale are reported from April, build through summer and thin by October. Humpback and other large rorqual records are rare and uneven, and a shore watcher should treat any single sighting as an event rather than a pattern. Basking shark, though not a cetacean, follow the same summer plankton and are logged in the same notebook. The month matters less than the year: a cold spring shifts everything late.

How does sea state decide what a watcher can name?

Sea state is the practical limit on identification. In a calm sea, a porpoise shows a low, rolling back and a brief blow that a watcher can follow with the naked eye. As the wind rises and the surface breaks into white, that same animal disappears into the texture, and only a larger species with a taller blow remains visible. The Douglas scale is the working tool here: at force 2 or 3, a careful observer can still track a minke at distance; at force 4 and above, the record becomes a list of probables. This is why a shore journal should note the wind with every entry. A sighting without a sea state is not evidence, it is an impression. Watchers who keep the two together find that their identification rate rises without any change in eyesight or equipment.

What does swell do that wind does not?

Swell is the part of the sea that arrives from elsewhere, and it is often present on a day with no local wind at all. A long groundswell from the Atlantic lifts the whole water column at the headland, so an animal that would show cleanly in a chop is instead hidden between two moving hills of water. The effect is worst at low angles of view, which is to say from a low shore. A watcher who can gain even a few metres of height, on a raised beach or a rock platform, changes the geometry and sees over the swell rather than through it. Swell also governs how long a blow stays visible. In a short sea, a blow is torn apart in a second or two. In a long swell, it can hang as a soft white mark long enough to be placed on a bearing.

Why is glare the hardest condition to work in?

Glare is the condition watchers underestimate, because it looks like good weather. A low sun across a calm sea turns the whole channel into a bright, moving sheet in which every small disturbance is a candidate and none can be confirmed. The countermeasures are simple and unglamorous. Watch with the sun behind you where the ground allows. Use the shaded side of a wall or a building. Work early and late in the day in summer, when the sun is low but the angle is workable, and accept that the middle hours of a bright afternoon are largely wasted. Polarised glasses help a little, though they flatten contrast as well as cutting reflection. A day of hard glare often produces a long list of possibles and no confirmed record, and the honest entry says so.

What should a shore record actually contain?

A useful entry is short and specific. It gives the date, the watch point, the time on and off, the wind direction and strength, the sea state, the swell, the visibility and the glare. Then it gives the animals: species where known, number, behaviour, bearing, distance, and whether the identification was confirmed or probable. Photographs are noted but not relied upon, since a distant back rarely photographs well from a headland. The value of the record lies in its consistency, not in its drama. A year of plain entries, kept in the same format, will show the arrival of the first minke, the last porpoise of winter and the weeks when the channel is simply empty. That pattern is the point, and it cannot be reconstructed later from memory.

How does a watcher plan a season on this coast?

The season is planned around conditions rather than dates. Spring offers long daylight and unsettled weather, so a watcher takes the calm windows when they come and expects gaps. High summer gives the best light and the most species, but also the flattest seas and the worst glare, which is why early mornings matter. Autumn brings the clearest air and the strongest swell, a combination that suits a raised watch point. Winter is for porpoise, grey seas and short days, and for reading the year's notes rather than adding to them. A watcher who accepts that most hours produce nothing will still, over a season, build a record that no single afternoon can match. The discipline is the same one that governs any long journey: choose the window, not the wish.

Sources

The material on this page was read back against the sources below on 15 September 2026. Each of them is a public page outside this journal and outside its own network, and each was consulted on the date given.

• https://www.nature.scot/, the page consulted for this entry, read back on 15 September 2026.
• https://www.snh.gov.uk/, the page consulted for this entry, read back on 15 September 2026.