Why do Costa Blanca anchorages have swell in light winds, and where can I find shelter?
I'm sailing along the Costa Blanca, and every anchorage we've tried has had enough swell to make us roll. The winds have been light for days, so where is it coming from, and how do I find somewhere quieter?
Answer
Swell is common in light winds on the Costa Blanca because waves generated elsewhere in the Mediterranean, or left over from earlier strong winds, can reach an anchorage long after the local breeze has dropped. Check the swell direction and period, then choose a bay with solid land between you and the incoming waves; wind shelter alone will not guarantee a quiet night.
Where swell comes from
Much of this coast faces the open Mediterranean to the east and south-east. Strong winds well offshore can send waves towards you while your stretch of coast remains almost windless. Earlier easterly weather can also leave a residual sea after the local wind has eased.
There are three common causes:
- Distant swell: fairly regular waves arriving in sets, generated outside your local weather area.
- Residual wind waves: a sea still settling after earlier wind, sometimes mixed with another wave system.
- Local waves or wakes: afternoon sea breezes, passing motorboats and commercial traffic can disturb an otherwise calm anchorage.
Repeated sets throughout the night suggest swell. A few isolated bursts followed by flat water suggest wakes. A headland may block the breeze while waves bend around its end, so calm air in the cockpit can mislead.
Read wave direction and period
Use a forecast showing significant wave height, wave direction and period, preferably with separate wind-wave and swell layers. Check the approach waters as well as the anchorage. A sheltered bay may be too small for the forecast model to resolve.
Wave direction normally describes where waves come from, but check the app's arrow convention. An easterly swell needs protection to your east, even if the wind is blowing offshore from the west.
Period is the interval between successive crests. A longer-period swell can reach farther around a headland and cause substantial rolling despite a modest forecast height. Even roughly 0.3 to 0.5 m arriving across the beam can spoil sleep on some yachts. Hull shape, loading and wave period all affect the result.
Check the forecast through the following morning, including changes in direction. Puertos del Estado's wave forecasts and buoy observations, alongside AEMET's coastal forecast, are useful sources. The nearest buoy gives a regional indication, not a measurement inside your chosen cala.
Shelter by swell direction
Many attractive calas are indentations in an exposed coastline rather than enclosed harbours. High cliffs provide excellent wind shelter without necessarily stopping the sea.