Keramas Alert Guide

Bali, Indonesia · part of the Keramas spot guide

Keramas is forecast-only — no usable buoy within thousands of kilometres — so it is a model-swell alert, and the height below is an open-ocean reading that the ridge amplifies on the face. Note the wind rule everyone gets backwards: the offshore is northwest off the mountain, and the southeast trades are the enemy.

The forecaster's checklist

1. 1.Decide which mode you’re forecasting — powerful dry-season south-southwest groundswell threading the Badung Strait, or the abundant wet-season east-to-south swell.
2. 2.For the powerful mode, find a deep Roaring Forties low aimed up the Indian Ocean and give it three to six days.
3. 3.Direction is everything — want south-southwest around 195–205° for size and power, remembering that west of about 205–225° gets shadowed by the Bukit and Nusa Penida.
4. 4.Read period — 13 seconds and up is the amplifying groundswell mode; 8 to 12 seconds is the smaller east-coast mode.
5. 5.Time the wind to dawn (the Mt Agung morning offshore is from the northwest, not the southeast) and the tide to mid-to-incoming; skip dead low over the lava.

Local winds & tide

Best wind: NW offshore — the Mt Agung morning wind (the SE trades are ONSHORE here) — from 290° to 340° (WNW–NNW).

Tide-critical though no tide series is modelled: best mid-to-incoming or high, when there’s enough water over the lava and the barrel lengthens; low exposes the sharp reef and fails to focus the swell.

Dial it in