Wave heights are generally measured two ways, Bascom Method and the Hawaiian scale. In scientific terms and most used by the surfing community around the world, the wave height is measured vertically from the trough to the crest and is known by surfers as face scale.
Measuring Wave Heights
The Bascom Method, developed by Willard Newell Bascom, is widely regarded as simple, fair, and rational; yet an overestimation most of the time. One stands on the beach with eyes aligned with the wave crest and the horizon. He or she then measures the wave from that point to the average sea level.
In Hawaii, local surfers use the back of the wave to measure wave height and is called Hawaiian scale or local scale. The history of Hawaiian scale and the conversion itself are widely discussed and debated. The conversion from face to Hawaiian is roughly 1/2 to 2/3 the size measured from trough to crest.
The Hawaiian Wave Scale has a few disadvantages, though:
- It is difficult when measuring small waves;
- It can’t be confirmed from the beach.
- It is based on emotional variables like courage.
- It does not measure the entire wave face in which surfers ride.
- It doesn’t apply to waves that are big and heavy but lack a large backside, like Teahupoo;
Wave Heights Face Scale in Feet (ft)
This list measures surfable wave face heights from the base to the lip. These are “standard” Non-Hawaiian wave heights. Hawaiians measure wave heights from the back of the wave, so their heights are typically about half that of the front face. A wave with a 9-foot face might be called a 3- to 4-foot wave in Hawaii.
Distance from Base to Lip of Wave
|1 – 2ft||Ankle to knee high|
|1 – 3ft||Ankle to waist high|
|2 – 3ft||Knee to waist high|
|2 – 3ft+||Knee to chest high|
|2 – 4ft||Knee to shoulder high|
|3 – 4 ft||Waist to chest high|
|3 – 4 ft||Waist to shoulder high|
|3 – 5 ft||Waist to head high|
|4 – 5 ft||Shoulder to head high|
|4 – 6 ft||Shoulder high to 1 foot overhead|
|4 – 7 ft||Shoulder high to 2 feet overhead|
|5 – 7 ft||Head high to 2 feet overhead|
|5 – 8 ft||Head high to 3 feet overhead|
|6 – 8 ft||Head high+ to 3 feet overhead|
|6 – 10 ft.||Head high+ to double overhead|
|8 – 10 ft.||3 feet overhead to double overhead|
|8 – 12 ft.||3 feet overhead to double overhead+|
|10 – 15 ft.||2 to 3 times overhead|
|12 – 15 ft.||Triple overhead|
|15 – 18 ft.||Triple overhead+|
|15 – 20 ft.||3 to 4 times overhead|
|18 – 20 ft.||4 times overhead|