In the Douglas Scale for measuring wave heights at sea, what word is used to describe waves of over 14 metres?

The word used by the Douglas Scale for waves over 14 metres is: Phenomenal

The Douglas Sea Scale is a scale which measures the height of the waves and also measures the swell of the sea. The scale is very simple to follow and is expressed in one of 10 degrees. The Douglas sea scale, also called the "international sea and swell scale", was devised in the 1920s by Captain H.P. Douglas, who later became vice admiral Sir Percy Douglas and hydrographer of the Royal Navy. Its purpose is to estimate the roughness of the sea for navigation. The scale has two codes: one code is for estimating the sea state, the other code is for describing the swell of the sea.

State of the sea (wind sea)

Degree Height (m) Description

• 0 no wave Calm (Glassy)
• 1 0–0.10 Calm (rippled)
• 2 0.10–0.50 Smooth
• 3 0.50–1.25 Slight
• 4 1.25–2.50 Moderate
• 5 2.50–4.00 Rough
• 6 4.00–6.00 Very rough
• 7 6.00–9.00 High
• 8 9.00–14.00 Very high
• 9 14.00+ Phenomenal