PAGASA Rainfall Warning Colours (Yellow, Orange, Red, Class Suspension)

Yesterday evening PAGASA issued Weather Advisory No. 60. No typhoon attached to it, no wind signal anywhere in the country, just a heavy rainfall outlook for the southwest monsoon running through this afternoon.

That kind of bulletin gets ignored by visitors and by a fair number of residents, because there is no storm name to attach it to. It is also the bulletin that has done nearly all of this month's damage.

The system it belongs to has three colours, and knowing which one you are looking at is more useful than knowing whether a typhoon exists.

Photographs here are stock images for illustration and are not pictures of the events described.

Yellow is the one people ignore

Yellow means rainfall of 7.5 to 15 millimetres per hour is observed or expected to continue.

The official wording is that flooding is possible in low-lying areas. In practice a yellow warning means the rain has already started and is heavy enough that somebody at a desk decided the public needed telling. It is not a forecast of what might happen later, it is a description of what is falling now.

Fifteen millimetres in an hour does not sound like much written down. It is enough to make a road undriveable if the drains are already full, which after two weeks of monsoon they are.

The reason to care about yellow is not yellow itself. It is that the colours escalate quickly and you would rather make your decision at yellow than at the next one.

Orange is where it turns

Orange means 15 to 30 millimetres per hour, and the official phrasing changes from possible to threatening.

At orange, communities are told to be alert for the possibility of evacuation. That is the tell. Yellow describes weather and orange starts describing what you might have to do about it.

This is the band where the practical decisions live. Whether the road out is still passable, whether the last ferry goes, whether you move the car. An orange warning that holds for several hours is doing more damage than a brief red one, because the total volume is what fills a river, not the peak rate.

And orange is common. This is not a rare alert that means something extraordinary is happening. In monsoon season on the west side of Luzon it can appear on an ordinary afternoon, which is exactly why people stop reacting to it.

Red means you are already late

Red is more than 30 millimetres per hour. There is a second trigger too: rain that has kept falling for three hours and passed 65 millimetres total.

The wording at red is serious flooding expected and evacuation is necessary. Not advisable. Necessary.

That second trigger is the one worth remembering, because it means a red warning does not require a dramatic downpour. Steady rain that simply refuses to stop for three hours gets you there. The sky at red does not necessarily look worse than the sky at orange.

By the time red is issued, the water that will flood your street has largely already fallen. Warnings describe rainfall, but flooding is what the ground does with rainfall an hour or two later. Treating red as the moment to start deciding is treating it as a forecast, and it is not one.

Class Suspension is a different decision

Here is the part that catches people, and it is genuinely counterintuitive.

The rainfall colours do not automatically close anything. Under the Department of Education's current rules, the automatic suspension of classes is tied to tropical cyclone wind signals, and it kicks in at Signal No. 3 or higher. Below that, at Signal No. 1 and 2, it is the local mayor's call. School heads and division superintendents handle heat and other local conditions.

Rainfall warnings are not in that automatic tier at all.

So you can have a red rainfall warning over a city, with streets flooding, and no automatic suspension anywhere, because there is no tropical cyclone and therefore no wind signal for the rule to attach to. It comes down to whether the mayor of that particular city declares one, and mayors declare at different thresholds on different days.

This is why announcements arrive at odd hours and why neighbouring cities do different things on the same morning. It is not disorganisation. It is a rule written around wind being applied to a hazard that is made of water.

For anyone travelling, the practical version is that you cannot infer anything about closures from the rainfall colour. You have to check the specific local government, and the rain warning is a signal to go looking rather than an answer in itself.

Why this beats watching for a typhoon

Most people planning a trip check whether there is a storm. It is the obvious thing to check and it is the wrong single question for this country in this season.

The rainfall warnings are issued per area and updated through the day by the regional forecasting divisions, which means they are far more local and far more current than any national storm bulletin. They also exist when no storm does, which is the situation right now and was the situation through most of the flooding this month.

A reasonable habit looks like this. Check whether there is a tropical cyclone, because that governs wind signals and closures. Then check the rainfall warning for the specific province or city you will be standing in, because that governs whether the roads work. Then, if either is active, check the local government's announcements, because that is where suspensions actually get declared.

Three checks, and only the first one is the one visitors normally do.

The colours have been around long enough that Filipinos read them without thinking about it, in the same way a Korean reads a heat advisory or a Japanese reads a seismic intensity number. Nobody explains them to you when you arrive, because to everyone local they are just the weather.

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