Albay, has historically been highly vulnerable to tropical cyclones due to its location along the typhoon belt and proximity to the Pacific Ocean. Major events include Super Typhoon Reming (Durian) in 2006, which caused devastating lahars from Mayon Volcano, flooding, and widespread destruction; Super Typhoon Rolly (Goni) in 2020, which brought extreme winds, storm surge, and heavy rainfall, prompting large-scale evacuations; Severe Tropical Storm Kristine in 2024, notable for record rainfall and flooding; and Tropical Storm Fengshen in 2025, which triggered evacuations due to rainfall and storm surge forecasts. Historical cyclones such as Typhoon Irving (1982) and Typhoon Betty (1980) also caused significant property damage and displacement. According to PAGASA, the hazards associated with these cyclones in Albay include strong winds, heavy rainfall leading to flash and riverine floods, storm surge in coastal areas, rough seas, lahars and landslides, particularly in areas surrounding Mayon Volcano, making preparedness and timely evacuation essential for local communities.
WHAT IS A TROPICAL CYCLONE?
Oceans and seas have great influence on the weather of continental masses. A large portion of the solar energy reaching the sea-surface is expended in the process of evaporation. These water evaporated from the sea/ocean is carried up into the atmosphere and condenses, forming clouds from which all forms of precipitation result. Sometimes, intense cyclonic circulations occur which is what we call the Tropical Cyclones.
Tropical cyclones are warm-core low pressure systems associated with a spiral inflow of mass at the bottom level and spiral outflow at the top level. They always form over oceans where sea surface temperature, also air temperatures are greater than 26°C. The air accumulates large amounts of sensible and latent heat as it spirals towards the center. It receives this heat from the sea and the exchange can occur rapidly, because of the large amount of spray thrown into the air by the wind. The energy of the tropical cyclone is thus derived from the massive liberation of the latent heat of condensation.
CLASSIFICATION OF TROPICAL CYCLONES
Tropical cyclones derive their energy from the latent heat of condensation which made them exist only over the oceans and die out rapidly on land. One of its distinguishing features is having a central sea-level pressure of 900 mb or lower and surface winds often exceeding 100 knots. They reach their greatest intensity while located over warm tropical waters and they begin to weaken as they move inland. The intensity of tropical cyclones vary, thus, we can classify them based upon their degree of intensity.
The classification of tropical cyclones according to the strength of the associated winds as adopted by PAGASA as of 23 March 2022 are as follows:
TROPICAL DEPRESSION (TD) – a tropical cyclone with maximum sustained winds of up to 62 kilometers per hour (kph) or less than 34 nautical miles per hour (knots).
TROPICAL STORM (TS) – a tropical cyclone with maximum wind speed of 62 to 88 kph or 34 – 47 knots.
SEVERE TROPICAL STORM (STS), a tropical cyclone with maximum wind speed of 87 to 117 kph or 48 – 63 knots.
TYPHOON (TY) – a tropical cyclone with maximum wind speed of 118 to 184 kph or 64 – 99 knots.
SUPER TYPHOON (STY) – a tropical cyclone with maximum wind speed exceeding 185 kph or more than 100 knots.
EFFECTS OF A TROPICAL CYCLONE
Tropical cyclone constitutes one of the most destructive natural disasters that affects many countries around the globe and exacts tremendous annual losses in lives and property. Its impact is greatest over the coastal areas, which bear the brunt of the strong surface winds, squalls, induced tornadoes, and flooding from heavy rains, rather than strong winds, that cause the greatest loss in lives and destruction to property in coastal areas.
STRONG WINDS
A squall is defined as an event in which the surface wind increases in magnitude above the mean by factors of 1.2 to 1.6 or higher and is maintained over a time interval of several minutes to one half hour. The spatial scales would be roughly 2 to 10 km. The increase in wind may occur suddenly or gradually. These development near landfall lead to unexpectedly large damage.
TORNADOES
Tornadoes are spawned by tropical cyclones and are expected to occur in about half of the storms with tropical storm intensity. These are heavily concentrated in the right front quadrant of the storm (relative to the track) in regions where the air has had a relatively short trajectory over land. These form in conjunction with strong convection.
RAINFALL AND FLOODING
Rainfallassociated with tropical cyclones is both beneficial and harmful. Although the rains contribute to the water needs of the areas traversed by the cyclones, the rains are harmful when the amount is so large as to cause flooding.
STORM SURGE
The storm surge is an abnormal rise of water due to a tropical cyclone and it is an oceanic event responding to meteorological driving forces. Potentially disastrous surges occur along coasts with low-lying terrain that allows inland inundation, or across inland water bodies such as bays, estuaries, lakes and rivers. For riverine situations, the surge is sea water moving up the river. A fresh water flooding moving down a river due to rain generally occurs days after a storm event and is not considered a storm surge. For a typical storm, the surge affects about 160 km of coastline for a period of several hours.
LAHARS AND LANDSLIDES
Lahars and landslides are significant hazards in Albay, particularly around Mount Mayon, during tropical cyclones. Lahars also called mudflows or volcanic debris flows are mixtures of volcanic debris and water. Geologists classify them into primary (hot) lahars, triggered by volcanic eruptions, and secondary (cold) lahars, caused by heavy rainfall. Tropical cyclones bring intense and prolonged rains that saturate volcanic ash, soil, and loose rocks on Mayon’s slopes, forming fast-moving slurries that can flow rapidly down river channels and valleys, destroying homes, infrastructure, and farmland. Similarly, landslides occur when saturated soils on steep slopes lose cohesion and slide downhill, blocking roads, damaging property, and endangering lives. Both hazards are intensified during cyclones, making early warning and evacuation critical for communities in high-risk areas.
SOURCE: PAGASA
