Coastal slang, common around the Chesapeake and the Gulf, for a low tide made much lower by a hard, sustained offshore wind, often behind a cold front. Water drains out of shallow bays and creeks, leaving boats aground in their slips, ferries cancelled and wide flats exposed. On the gauge it is a large negative residual, and it can last through more than one tidal cycle.
Northwest wind all night gave us a blowout tide, half the boats in the creek are sitting on the mud.
Blowout lows are a navigation hazard as well as a nuisance: charted depths can be unavailable for a whole day, not just at the bottom of the tide.
Also heard as
- blow-out tide
- blowout
Related terms
Set-down
A drop in water level below the predicted tide caused by winds blowing water away from the coast.
Residual
The observed water level minus the predicted tide, showing the effect of weather, rivers and other non-tidal causes.
Minus tide
A low tide predicted to fall below the chart datum zero, shown as a negative number in the tide table.
Dead low
The very bottom of low water, when the tide has stopped falling and not yet started to rise.