The Denpasar Regional Meteorology, Climatology, and Geophysics Agency (BBMKG) has issued an early warning of high waves in several waters surrounding Bali.
The phenomenon, triggered by strong winds and atmospheric pressure differences between Australia and Indonesia, is expected to persist until at least 9 August 2025.
According to Aryantika, a forecaster from BBMKG Region III Denpasar, the wave heights could reach between 4 and 6 metres, particularly in the southern part of the Bali Strait, the Badung Strait, the southern Lombok Strait, and the southern waters of Bali Island.
“This poses a risk to shipping around the Bali region. We always urge fishermen or marine tourism operators to remain vigilant about the height of these sea waves,” Aryantika told RRI on Sunday, 3 August 2025.
She explained the pressure disparity behind the current weather pattern.
“There is significant air pressure, causing a high air flow from Australia to Indonesia, where the pressure is lower. This pressure increases wind speed, which triggers higher waves.”
Wayan Musteana, Head of the Operational Meteorology Working Group at BBMKG Region III, also stated that winds in the region are currently strong.
“In the waters north of Bali, winds blow from the southeast to the south, while in the southern waters, winds tend to blow from the east to the southeast.
Wind speeds in both areas can reach 20 knots or about 37 kilometres per hour, increasing the potential for high waves,” he explained.
Several key maritime routes are directly affected, including the Bali Strait (connecting Bali and Java), the Lombok Strait, the Badung Strait (used frequently for crossings to Nusa Penida), and the southern fishing zones of Bali.
In addition to southern waters, wave heights of up to 4 metres are expected in the northern part of the Lombok Strait, and up to 2.5 metres in the northern waters of Bali.
BBMKG advises that small vessels and operators should be cautious. Wayan Musteana added, “Maritime safety is the top priority. Please always check the weather forecast before engaging in activities at sea.”
The agency also outlines vessel safety thresholds:
- Fishing boats: beware of winds over 15 knots (27 km/h) and waves over 1.25 metres.
- Barges: use caution at 16-knot winds and 1.5-metre waves.
- Ferry boats: extra care at 21-knot winds and 2.5-metre waves.
BBMKG has coordinated with port authorities and transport operators to ensure the timely dissemination of updates. Tourists planning to travel to Nusa Penida or Lombok are advised to follow official guidelines and delay crossings if necessary.
Waterblow Nusa Dua Temporarily Closed After High Waves
High waves impacted Bali’s Nusa Dua area on Wednesday morning, 6 August 2025, prompting the temporary closure of the Waterblow Peninsula tourist site. A viral video captured the forceful sea conditions as waves crashed into the attraction, which is popular for its ocean spray views.
General Manager of The Nusa Dua, I Made Agus Dwiatmika, confirmed the closure. “This decision was made based on the findings of ITDC’s operational team on-site. We also referenced the BMKG’s warning regarding the potential for high waves predicted to occur between August 6–9, 2025,” he told Detiknews.
While damage was minor, the Indonesia Tourism Development Corporation (ITDC) took preventive action to mitigate risk and ensure public safety.
“On Peninsula Island, we have deployed additional security personnel in high-risk areas, particularly around Waterblow and Pura Bias Tugel. This includes installing wave warning signs and coordinating with the caretakers of Pura Bias Tugel to ensure the safety and comfort of visitors as well as the security of the sacred area,” Agus explained.
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He also confirmed enhanced security measures on nearby Nusa Dharma Island. “We have increased patrols and surveillance, especially along pedestrian paths and public areas near the coastline. Security personnel are also on standby to prevent uncontrolled visitor movement to high-risk areas,” he added.
Agus noted that wave conditions around Waterblow improved by Wednesday afternoon and that the situation remains under control. The reopening of the site will be determined based on continued weather assessments.
