Five names for the same kind of system at five strengths. Knowing which is which tells you how seriously to take a forecast, and what it does not tell you.
"There is an LPA." "It has become a tropical depression." "It is now a typhoon." The names change every few hours during a developing system, and most people are not sure what the steps mean.
Here is the ladder, and more importantly, what it does and does not tell you about your property.
Low pressure area (LPA). An area of relatively low atmospheric pressure with cloud and rain, but without an organised circulation strong enough to be classified further. An LPA is not a storm and it can still deliver a lot of rain.
Tropical depression. Organised circulation with maximum sustained winds up to 61 km/h.
Tropical storm. Winds of 62 to 88 km/h.
Severe tropical storm. Winds of 89 to 117 km/h.
Typhoon. Winds of 118 to 184 km/h.
Super typhoon. Winds above 185 km/h.
PAGASA is the authority on these classifications and on every forecast. The thresholds above are the categories they use; treat their bulletins as the source, not any summary.
Every step is defined by wind. Not by rain.
That means a tropical depression, sitting near the bottom of the ladder, can produce far more flooding than a typhoon that moves through quickly. The category tells you about wind. It does not rank the flood risk.
The Philippines has repeated examples. Ondoy in 2009 was a tropical storm at its worst for Metro Manila and produced record flooding. Sendong in 2011 was not an especially strong system by wind and killed more than a thousand people with water.
So watch two things separately: the storm category, and the rainfall warnings. The rainfall side is explained in PAGASA rainfall warnings and your address, and the wind side in wind signals explained.
Speed of movement. A slow system dumps rain in one place for longer. A fast one is over sooner. Two typhoons of identical strength can produce very different floods.
Size. A compact intense storm affects a narrow band. A large one affects a wide area at lower intensity.
Where the rain falls. Rain bands are not symmetrical and the heaviest rain is often not at the centre.
What the ground was already doing. A moderate storm arriving after two weeks of rain is more dangerous than a strong one arriving on dry ground.
The habagat enhancement. A storm passing well north of the country can pull the southwest monsoon over Luzon and produce days of flooding without ever making landfall. See habagat season.
Your address. Mapped flood susceptibility, elevation, slope, landslide susceptibility, storm surge exposure and distance to the nearest mapped waterway describe the ground. They are the same for an LPA and for a super typhoon.
The category tells you how much water and wind might arrive. The screening tells you what your specific point does when it does.
PAGASA is the sole authority on tropical cyclone classification, tracks, warnings, and rainfall advisories. A hazard screening does not forecast anything. It reports what public national datasets say about the ground at your coordinates, which is the part that stays the same while the names on the news change.
CheckHazard does not replace a professional geotechnical or engineering survey.