Public Storm Warning Signal

When any Public Storm Warning Signal Number is hoisted or put in effect for the first time, the corresponding meteorological conditions are not yet prevailing over the locality. This is because the purpose of the signal is to warn the impending occurrence of the given meteorological conditions. It must be noted also that the approximate lead time to expect the range of the wind speeds given for each signal number is valid only when the signal number is put in effect for the first time. Thus, the associated meteorological conditions are still expected in at least 36 hours when PSWS #1 is put in effect initially; in at least 24 hours with PSWS #2; in at least 18 hours with PSWS #3, in at least 12 hours with PSWS #4; and in at least 12 hours with PSWS #5. The lead time shortens correspondingly in the subsequent issues of the warning bulletin when the signal number remains in effect as the tropical cyclone comes closer.


It is also important to remember that tropical cyclones are constantly in motion; generally towards the Philippines when PAGASA is issuing the warning. Therefore, the Public Storm Warning Signal Number over a threatened/ affected locality may be sequentially upgraded or downgraded. This means that PSWS #1 may be be upgraded to PSWS #2, then to PSWS #3, PSWS #4 and to PSWS #5 as necessary when a very intense typhoon is approaching or downgraded when the typhoon is moving away. However, in case of rapid improvement of the weather condition due to the considerable weakening or acceleration of speed of movement of the tropical cyclone moving away from the country, the downgrading of signal may jump one signal level. For example, PSWS #3 may be downgraded to PSWS #1 or all signals from PSWS #2 may be lowered.

The delineation of areas for a given signal number is based on the intensity, size of circulation and the forecast direction and speed of movement of the tropical storm or typhoon at the time of issue of the warning bulletin. The change in intensity, size of circulation or movement of the tropical cyclone also determines the change in the PSWS number over a given locality.



Tropical Cyclone Warning Signal






Tropical Cyclone Warning Signal #1

WINDS: 30-60 kph may be expected in at least 36 hr
SEA CONDITIONS (Open Sea)
Wave Height: 1.25-4.0 meters

DAMAGE TO STRUCTURE:

  • Very light or no damage to high risk structures,
  • Light to medium and low risk structures
  • Slight damage to some houses of very light materials or makeshift structures in exposed communities.

DAMAGE TO VEGETATION:
  • Some banana plants are tilted, a few downed and leaves are generally damaged
  • Twigs of small trees may be broken.
  • Rice crops, however, may suffer significant damage when it is in its flowering stage.

Tropical Cyclone Warning Signal #2

WINDS: 61-120 kph may be expected in at least 24 hr
SEA CONDITIONS (Open Sea)
Wave Height:4.1-14.0 m
Storm surge possible at coastal areas.

DAMAGE TO STRUCTURE:

  • Light to Moderate damage to high risk structures;
  • Very light to light damage to medium-risk structures;
  • No damage to very light damage to low risk structures
  • Unshielded, old dilapidated schoolhouses, makeshift shanties, and other structures of light materials are partially damaged or unroofed.
  • Some old galvanized iron (G.I.) roofs may be peeled or blown off.
  • Some wooden, old electric posts are tilted or downed.
  • Some damage to poorly constructed signs/billboards.

DAMAGE TO VEGETATION:
  • Most banana plants, a few mango trees, ipil-ipiland similar trees are downed or broken.
  • Some coconut trees may be tilted with few others broken.
  • Rice and corn may be adversely affected.
  • Considerable damage to shrubbery and trees with some heavy-foliaged trees blown down.

Tropical Cyclone Warning Signal #3

WINDS: 121-170 kph may be expected in at least 18 hr
SEA CONDITIONS (Open Sea)
Wave Height: > 14.0 meters
Storm surge possible at coastal.

DAMAGE TO STRUCTURE:

  • Heavy damage to high–risk structures;
  • Moderate damage to medium-risk structures;
  • Light damage to low-risk structures
  • Increasing damage to old, dilapidated residential structures and houses of light materials (up to 50% in a community)
  • Houses of medium strength materials (old, timber or mixed timber-CHB structures, usually with G.I. roofings), some warehouses or bodega-type structures are unroofed

DAMAGE TO VEGETATION:
  • Almost all banana plants are downed, some big trees (acacia, mango, etc.) are broken or uprooted,
  • Dwarf-type or hybrid coconut trees are tilted or downed
  • Considerable damage to shrubbery and trees with heavy foliage blown off; some large trees blown down.

Tropical Cyclone Warning Signal #4

WINDS: 171-220 kph may be expected in at least 12 hr
SEA CONDITIONS (Open Sea)
Wave Height: more than 14.0 meters
Storm surge 2-3m possible at coastal areas.

DAMAGE TO STRUCTURE:

  • Very heavy damage to high –risk structures.
  • Heavy damage to medium risk structures;
  • Moderate damage to low-risk structures
  • Considerable damage to structures of light materials (up to 75% are totally and partially destroyed); complete roof structure failures.
  • Many houses of medium-built materials are unroofed, some with collapsed walls; extensive damage to doors and windows
  • A few houses of first-class materials are partially damaged
  • All signs/billboards are blown down.

DAMAGE TO VEGETATION:
  • There is almost total damage to banana plantation,
  • Most mango trees, ipil-ipiland similar types of large trees are downed or broken.
  • Coconut plantation may suffer extensive damage.
  • Rice and corn plantation may suffer severe losses.

Tropical Cyclone Warning Signal #5

WINDS:  > 220 kph may be expected in at least 12 hr
A Super Typhoon will affect the locality.

SEA CONDITIONS (Open Sea)
Wave Height: more than 14.0 m
Storm surge more than 3 meters possible at coastal areas

DAMAGE TO STRUCTURE:

  • Widespread damage to high-risk structures
  • Very heavy damage to medium-risk structures
  • Heavy damage to low-risk structures;
  • Almost total damage to structures of light in highly exposed coastal areas.
  • Complete roof failure on many residences and industrial buildings. Severe and extensive window and door damage
  • Most residential and institutional buildings of mixed construction may be severely damaged.
  • Electrical power distribution and communication services severely disrupted.
  • All signs/billboards blown

DAMAGE TO VEGETATION:
  • Total damage to banana plantation
  • Most tall trees are broken, uprooted or defoliated;
  • Coconut trees are stooped, broken or uprooted.
  • Few plants and trees survived