thirteen forces of wind — from water like a mirror to a wave of fourteen metres
Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.
Three sizes in one archive — from a sheet on the fridge to a poster on the wall.
The force and its name on the left, then the limits of wind speed in knots and metres per second, then the probable and the probable maximum wave height in the open sea.
The Met Office defines the scale as an empirical measure of wind intensity based on observed sea conditions: the force is measured by what can be seen from the deck, and the speeds stand beside that description rather than in place of it.
Double the wind and the wave trebles rather than doubles: from force 7 to force 11 the mean wind goes from 30 knots to 60, and the probable wave from 4.0 metres to 11.5. Across every such pair in this table the wave grows by a factor of 2.3 to 3.3.
The sea lags behind the wind, though: these heights are for well-developed waves of the open sea, so a wind that has only just got up reads off the water weaker than it is.
Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 4 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.
from the Challenger Deep to the summit of Everest · one scale, nothing compressed
what differs inside the cell · and a paper describing each mode
from the first synapsid to us · 320 million years on one axis
when each group appeared · five hundred million years on one axis