THE SAFFIR-SIMPSON TROPICAL CYCLONE SCALE (SSTC)

A. TROPICAL DEPRESSION AND TROPICAL STORM CATEGORIES:


1) TROPICAL STORM CATEGORY A: WEAK TROPICAL STORM

MSW: 30-49 mph (26-43 kt)

Peak Gusts: 40-64 mph (33-56 kt)

Potential Damage - Damage done to only the flimsiest lean-to type structures. Unsecured light signs blown down. Minor damage to banana trees [Musa spp.] and near-coastal agriculture, primarily from salt spray. Some small dead limbs, ripe coconuts, and dead palm fronds blown from trees. Some fragile and tender green leaves blown from trees such as papaya [Carica papaya] and fleshly broad leaf plants.

Coastal Inundation and Wave Action - On windward coasts, sea level rise of less than 2 ft (0.7) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 2-3 ft (0.7-1.0m); less than 1 ft (0.3m) of additional water over reefs. Rough surf at reef margin with moderately strong along-shore currents (rip tides) inside reefs.



2) TROPICAL STORM CATEGORY B: SEVERE TROPICAL STORM

MSW: 50-73 MPH (44-63 kt)

Peak Gusts: 65-94 mph (57-81 kt)

Potential Damage - Minor damage to buildings of light material; major damage to huts made of thatch or loosely attached corrugated sheet metal or plywood. Unattached corrugated sheet metal and plywood may become airborne. Wooden signs not supported with guy wires are blown down. Moderate damage to banana trees [Musa spp.], papaya trees [Carica papaya], and most fleshy crops. Large dead limbs, ripe coconuts, nay dead palm fronds, some green leaves, and small branches are blown from tree.


Coastal Inundation and Wave Action - On windward coasts, sea level rise of 2-4 ft (0.7-1.2 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 4-6 ft (1.2-1.8 m); 1-2 ft (0.3-0.7 m) of additional water over reefs. Very rough surf at reef margin with strong along-shore currents (rip tides) inside reefs.



 

B. TYPHOON AND SUPER TYPHOON CATEGORIES:


1) TYPHOON CATEGORY 1: MINIMAL TYPHOON

MSW: 74-95 mph (64-82 kt)

Peak Gusts: 95-120 mph (82-105 kt)

Potential Damage - Corrugated metal and plywood stripped from poorly constructed or termite-infested structures and may become airborne. A few wooden, non-reinforced power poles tilted, and some rotten power poles broken. Some damage to poorly constructed, loosely attached signs. Major damage to banana trees [Musa spp.], papaya trees [Carica papaya], and fleshy crops. Some young trees downed when the ground is saturated. Some palm fronds crimped and bent back through the crown of coconut palms [Cocos nucifera]; a few palm fronds torn from the crowns of most types of palm trees; many ripe coconuts blown from coconut palms. Less than 10% defoliation of shrubbery and trees; up to 10% defoliation of tagantangan [Leucaena spp.]. Some small tree limbs downed, especially from large bushy and frail trees such as mango [Mangifera spp.], African tulip [Spathodea campanulat], Poinciana [Delonix regia], et. Overall damage can be classified as minimal

Coastal Inundation and Wave Action - On windward coasts, sea level rise of 4-5 ft (1.2-1.5 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 5-7 ft (1.5-2.1 m) above normal; 2-3 ft (0.6-1.0 m) of additional water over reefs. Wind driven waves may inundate low-lying coastal roads where reefs are narrow. Minor pier damage. Some small craft in exposed anchorages break moorings.



2) TYPHOON CATERGORY 2: MODERATE TYPHOON

MSW: 96-110 mph (83-95 kt)

Peak Gusts: 121-139 mph (106-121 kt)

Potential Damage - Several rotten wooden power poles snapped and many non-reinforced wooden power poles tilted. Some secondary power lines downed. Damage to wooden and tin roofs, and doors and windows of termite-infested or rotted wooden structures, but no major damage to well-constructed wooden, sheet metal, or concrete buildings. Considerable damage to structures made of light materials. Major damage to poorly constructed, attached signs. Exposed banana trees [Musa spp.] and papaya trees [Carica papaya] totally destroyed; 10-20% defoliation of trees and shrubbery; up to 30% defoliation of tangantangan [Leucaena spp.]. Light damage to sugar can [Saccharum spp.] and bamboo [Bambusa spp.]. Many palm fronds crimped and bent through the crown of coconut palms [Cocos nucifera] and several green fronds ripped from palm trees. Some green coconuts blown from trees. Some trees blown down, especially shallow rooted ones such as acacia [Acacia spp.]. mango [Mangifera indica] and breadfruit [Artocarpus spp.] when the ground becomes saturated. Overall damage can be classified as moderate.

Coastal Inundation and Wave Action - On windward coasts, sea level rise of 6-8 ft (1.8-2.4 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 7-9 ft (2.1-2.7 m) above normal; 3-5 ft (1.0-1.5 m) of additional water over reefs. Wind-driven waves will inundate low-lying coastal roads below 4 ft (1.0 m) on windward locations where reefs are narrow. Some erosion of beach areas, some moderate pier damage, and some large boats torn from moorings.



3) TYPHOON CATEGORY 3: STRONG TYPHOON

MSW: 111-130 mph (96-113 kt)

Peak Gusts: 121-139 mph (106-121 kt)

Potential damage - A few non-reinforced hollow-spun concrete power poles broken or tilted and may non-reinforced wooden power poles broken or blown down; many secondary power lines downed. Practically all poorly constructed signs blown down and some stand-alone steel-framed signs bent over. Some roof, window, and door damage to well-built, wooden and metal residences and utility buildings. Extensive damage to wooden structures weakened by termite infestation, wet-and-dry wood rot, and corroded roof straps (hurricane clips). Non-reinforced cinderblock walls blown down. Many mobile homes and buildings made of light materials destroyed. Some glass failure due to flying debris, but only minimal glass failure due to pressure forces associated with extreme gusts. Some unsecured construction cranes blown down. Air is full of light projectiles and debris. Major damage to shrubbery and trees; up to 50% of palm fronds bent or blown off; numerous ripe and many green coconuts blown off coconut palms; crowns blown from a few palm trees. Moderate damage to sugar cane [Saccharum spp.] and bamboo [Bambusa spp.]. Some large trees [palm trees, breadfruit [Artocarpus spp.], monkeypod [Samanea saman], mango [Mangifera indica], acacia [Acacia spp.] and Australian pines [Cauarina spp.]} blown down when the ground becomes saturated; 30-50% defoliation of most trees and shrubs; up to 70% defoliation of tangantangan [Leucaena spp.]. Some very exposed panax [Polyscias spp.], tangantangan [Leucaena spp.], and oleander [Nerium oleander] bent over. Overall damage can be classified as extensive.

Coastal Inundation and Wave Action. On windward coasts, sea level rise of 9-12 ft (2.7-3.6 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 11-14 ft (3.3-4.2 m) above normal; 5-7 ft (1.5-2.1 m) of additional water across reefs. Wind-driven waves will inundate low-lying coastal roads below 7 ft (2.1 m) of elevation on windward locations where reefs are narrow. Considerable beach erosion. Many large boats and some large ships torn from moorings.



4) TYPHOON CATEGORY 4: VERY STRONG TYPHOON MSW: 131-155 mph (114-135 kt) 

Peak Gusts: 166-197 mph (145-171 kt)

Potential Damage - Some reinforced hollow-spun concrete and many reinforced wooden power poles blown down; numerous secondary and a few primary power lines downed. Extensive damage to non-concrete roofs; complete failure of many roof structures, window frames and doors, especially unprotected, non-reinforced ones; many well-built wooden and metal structures severely damaged or destroyed. Considerable glass failures due to flying debris and explosive pressure forces created by extreme wind gusts. Weakly reinforced cinderblock walls blown down. Complete disintegration of mobile homes and other structures of lighter materials not tied down. Most small and medium-sized steel-framed signs bent over of blown down. Some secured construction cranes and gantry cranes blown down. Some fuel storage tanks may rupture. Air is full of large projectiles and debris. Shrubs and trees 50-90% defoliate; up to 100% of tangantangan (Leucaena spp.) defoliated. Up to 75% of palm fronds bent, twisted, or blown off; many crowns stripped from palm trees. Numerous green and virtually all ripe coconuts blown from trees. Severe damage to sugar cane [Saccharum spp.] and bamboo [Bambusa spp.]. Many large trees blown down [palms, breadfruit [Artocarpus spp.], monkeypod [Samanea saman], mango [Mangifera indica], acacia [Acacia spp.], and Australian pine (Casuarina spp.). Considerable bark and some pulp removed from trees; most standing trees are void of all but the largest branches (severely pruned), with remaining branches stubby in appearance; numerous trunks and branches are sandblasted. Patches of panax [Polyscias spp.], tangantangan [Leucaena spp.], and oleander [Nerium oleander] are flattened. Overall damage can be classified as extreme.

Coastal Inundation and Wave Action - On windward coasts, sea level rise of d13-18 ft (3.9-5.5 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can reach 15-24 ft (4.5-7.3 m) above normal; 8-12 ft (2.4-3.7 m) of additional water over reefs. Wind-driven waves will inundate coastal areas below 12 ft (3.7 m) elevation. Large boulders carried inland with waves. Severe beach erosion. Severe damage to port facilities including some loading derricks and gantry cranes. Most ships torn from moorings.



5) TYPHOON CATEGORY 5: DEVASTATING TYPHOON

MSW: 156-194 mph (136-170 kt)

Peak Gusts: 198-246 mph (172-216 kt)

Potential Damage - Severe damage to some solid concrete power poles, to numerous reinforced hollow-spun concrete power poles, to many steel towers, and to virtually all wooden poles; all secondary power lines and most primary power lines downed. Total failure of non-concrete reinforced roofs. Extensive or total destruction to non-concrete residences and industrial buildings. Some structural damage to concrete structures, especially from large debris, such as cars, large appliances, etc. Extensive glass failure due to impact of flying debris and explosive pressure forces during extreme gusts. Many well-constructed storm shutters ripped from structures. Some fuel storage tanks rupture. Nearly all construction cranes blown down. Air full of very large and heavy projectiles and debris. Shrubs and trees up to 100% defoliated; numerous large trees blown down. Up to 100% of palm fronds bent, twisted, or blown off; numerous crowns blown from palm trees; virtually all coconuts blown from trees. Most bark and considerable pulp removed from trees. Most standing trees are void of all but the largest branches, which are very stubby in appearance and severely sandblasted. Overall damage can be classified as catastrophic.

Coastal Inundation and Wave Action - On windward coasts, sea level rise of >25 ft (>7.6 m) above normal in open bays and inlets due to storm surge and wind-driven waves; breaking waves inside bays can be > 30 ft 99.2 m) above normal; 12-18 ft (3.7-5.5 m) of additional water over reefs. Serious inundation likely for windward coastal areas below 18 ft (5.5m) elevation. Very large boulders carried inland with waves. Extensive beach erosion. Extensive damage to port facilities including most loading derricks, gantry cranes, and fuel piers. Virtually all ships, regardless of size, torn from moorings and many sunk.

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