Storm surge, or daluyong ng bagyo
The sea rising over the coast because a typhoon is pushing it there. It is not a tsunami, it does not arrive like one, and the warning for it comes in metres.
Written for the Philippines. Daluyong ng bagyo ang tawag dito ng PAGASA.
What it is
PAGASA calls it the abnormal rise in sea level that happens during a tropical cyclone, and gives it the Filipino name daluyong ng bagyo. It is caused by the strong winds and the low atmospheric pressure of the cyclone itself. As the storm comes towards the coast, the wind pushes ocean water over low-lying ground, and that is what floods.
Two things make it worse, and both are theirs. It becomes more dangerous when it arrives on top of a high tide, which can flood ground that would otherwise have stayed dry. And on top of the surge itself come the big waves the same winds are generating.
Source: PAGASA, Storm Surge. Read 23 September 2026. The definition, the Filipino name, the cause, the three factors and the wording of the advice are from that page. The warning level heights and their impacts are set out there as a coloured table image with no text alternative, so the rows were read from the image, the same way the PHIVOLCS drill primer and the rainfall warning icons were.
The heights PAGASA warns at
| Warning | Estimated height | What PAGASA expects it to do |
|---|---|---|
| Yellow | Under 2 metres | Minimal to moderate damage to communities, coastal and marine infrastructure, and disruptions to all marine-related activities. |
| Orange | 2 to 3 metres | Moderate to significant damage to communities, coastal and marine infrastructure, and disruptions to all marine-related activities. Significant erosion to beaches. Possible river flooding due to storm surge. |
| Red | Over 3 metres | Significant damage to communities, coastal and marine infrastructure, and disruptions to all marine-related activities. Significant erosion to beaches. Possible river flooding due to storm surge. |
The orange and red rows describe almost the same damage, and that is how PAGASA writes them: red drops the word moderate. The line that actually separates them is the height.
Source: PAGASA, Storm Surge. Read 23 September 2026.
Why it is not a tsunami
This is not a pedantic distinction, and it is not one this site invented. PHIVOLCS says on its own tsunami page that a tsunami is erroneously called a tidal wave and is sometimes mistakenly associated with storm surges.
Storm surge
- Caused by weather Wind and low pressure in a tropical cyclone, pushing the sea inland.
- It comes with the storm You are told a cyclone is coming, and the surge forecast comes with it.
- Warned in metres PAGASA forecasts an estimated height, in the three bands above.
Source: PAGASA, Storm Surge. Read 23 September 2026.
Tsunami
- Caused by the seabed moving A series of sea waves, commonly from an under-the-sea earthquake shallow enough and strong enough to displace the seabed.
- It can arrive in minutes A local tsunami, generated within about a hundred kilometres, can reach the shoreline in two to five minutes. A distant one takes one to twenty four hours.
- No storm needed The weather can be clear. The shaking is the warning.
Source: PHIVOLCS, Introduction to Tsunami. Read 23 September 2026.
What PAGASA weighs
For a community exposed to storm surge, they name three considerations as the most important.
- The strength of the tropical cyclone
- The height of the surge
- Whether the community sits in a low-lying area
What to do about it
PAGASA puts it in one sentence, and it is worth reading as the whole of their advice: the only way to reduce the effects is to keep checking weather updates, to prepare ahead of time, and to move to high ground when a mandatory evacuation is called.
High ground, not an upper floor. A surge that reaches three metres is above the ceiling of a single-storey house, and the water keeps coming for as long as the wind holds it there.
Source: PAGASA, Storm Surge. Read 23 September 2026.
The typhoon guide and the wind signals The rainfall warnings