Typhoon Hazard Group 1 PDF

HYDROMETEOROLOGICAL HAZARD: TYPHOON Group 1 TYPHOON A typhoons are intense storm systems characterized by strong winds, heavy rainfall, and sometimes storm surges, which can cause significant damage to coastal areas. It contains winds rotating counterclockwise, with a speed of 118-...

HYDROMETEOROLOGICAL HAZARD: TYPHOON Group 1 TYPHOON A typhoons are intense storm systems characterized by strong winds, heavy rainfall, and sometimes storm surges, which can cause significant damage to coastal areas. It contains winds rotating counterclockwise, with a speed of 118-220 kilometers per hour. It could also develop into a super typhoon if the wind speed exceeds 220 kilometers per hour. In other parts of the world, these are referred to as hurricane, typhoons, or simply tropical cyclones depending on the region.  TYPHOON, CYCLONE, AND HURRICANE Hurricanes are tropical storms that form over the North Atlantic Ocean and Northeast Pacific. Cyclones are formed over the South Pacific and Indian Ocean. Typhoons are formed over the Northwest Pacific Ocean. The impending signs of a typhoon are felt when it is close to landfall. These include the following: Increased ocean swell Changes in Clouds Barometric Pressure drop 1. Abrupt changed in wind speed. 1. Increased ocean swell – A swell in a series of ocean waves brought about by strong winds. An incoming typhoon would cause a swell of about a meter in height that hit the shore every 10 seconds. As the typhoon approaches the waves to come in much faster and may also increase in height. 2. Changes in clouds – Cumulus clouds may fill the sky about 36 hours before a typhoon. As the storm approaches, the sky could be clear of clouds and may later have a mass of cirrus clouds which appear as a veil covering the horizon, eventually covering a large portion of the sky. A few hours before the typhoon landfall, low-lying clouds form which slowly become thick and dark, usually accompanied by rain. 3. Barometric pressure drop – The atmospheric pressure may start to drop about 36 hours before typhoon landfall. This will continue as the storm approaches. 4. Abrupt changes in wind speed – wind speed increases due to the drop in atmospheric pressure as air moves from an area with high pressure to low pressure. The increase in wind speed also increases the height of the ocean swell.  CLASSIFICATION OF TYPHOON Classification Wind (KPH) Impacts of the wind Tropical Depression No damage to very 60 km/h or less (TD) light damage Light to moderate Tropical Storm (TS) 62-88 km/h damage Severe Tropical Moderate to heavy 89-117 km/h Storm (STS) damage Heavy to very heavy Typhoon (TY) 118-184 km/h damage Super Typhoon Very heavy to 185 km/h or higher (STY) widespread damage HOW DOES TYPHOON FORM? A typhoon forms when winds blow into areas of the ocean where the water is warm. These winds collect moisture and rise, while colder air moves in below. This creates pressure, which causes the winds to move very quickly. The winds rotate, or spin, around a center called an eye. EFFECTS OF TYPHOON Heavy Rainfall and Flooding - Typhoons bring intense rainfall, which can cause severe flooding in both coastal and inland areas, leading to destruction of homes, roads, and infrastructure. Strong Winds - Typhoons produce extremely strong winds, which can damage buildings, uproot trees, and down power lines. Storm Surges - The strong winds and low pressure of typhoons can cause the sea level to rise, leading to storm surges that flood coastal areas. 1. Landslides - Continuous heavy rainfall can cause soil erosion, leading to landslides, especially in hilly or mountainous regions. Typhoon Haiyan (Yolanda) – 2013 One of the strongest tropical cyclones ever recorded. Hit the Philippines, particularly Tacloban, causing widespread devastation. Winds: 315 km/h (195 mph), resulted in over 6,000 fatalities  Mitigating the Destructive Effects of Typhoon 1. Determine the areas prone to typhoon-related disaster Certain routes can be observed to be more or less consistently traversed by typhoons. Observation of these typhoon tracks allow typhoon paths to be established. This will help in identifying priority areas for directing efforts and resources to mitigate the hazards associated with the passage of tropical cyclone. 2. Implementing legislation Areas that are prone to typhoon-related hazards like flooding, landslides, or storm surges should be carefully planned. Laws can ensure that high-risk areas are not used for buildings or activities that could endanger people or harm the environment. 3. Weather forecasting and monitoring Effective forecasting and monitoring of tropical cyclones gives ample time for communities to prepare, secure property, and to seek refuge, if necessary. It also gives a lead time for the different businesses involved, for example, in agriculture, transportation, and energy generation to make decisions and necessary arrangements to minimize the possible losses. *PAGASA 4. Effective Public Typhoon Warning Systems 5. PSWS #1-Cyclone winds of 30-60 km/h are expected within the next 36 hours. Its winds not expected to bring damage but may bring very light damage. 6. PSWS #2-Cyclone winds of 61-120 km/h are expected within the next 24 hours. Light to moderate damage. 7. PSWS #3-Cyclone winds of 121-170 km/h are expected within the next 18 hours. Moderate to heavy damage. 8. PSWS #4-Cyclone winds of 171-220 km/h are expected within the next 12 hours. Heavy to very heavy damage. PSWS #5-Cyclone winds of more than 220 km/h are expected within the next 12 hours. Very heavy to widespread damage.  PAGASA Philippine and Atmospheric, Astronomical Geophysical Services Administration (PAGASA) is the Philippine national institution dedicated to provide flood and typhoon warnings, public weather forecasts and advisories, meteorological, astronomical, climatological, and other specialized information and services primarily for the protection of life and property and in support of economic, productivity and sustainable development.  WEATHER FORECAST Weather forecast is a scientific estimate of future weather condition, wherein a weather condition is a state of the atmosphere at a given time expressed in terms of the most significant variables. In the Philippines, cloudiness, rainfall and wind are the weather parameters with significant variation, and therefore of interest to the forecast users. HOW WEATHER FORECAST IS MADE? Weather forecasting is done by a Meteorologist; he/she must know about the existing weather condition over a large area. The accuracy of forecast decision is based on forecasting tools known as the Weather Map. The weather map displays the air pressure, wind, temperature, and humidity distribution trends at various atmospheric rates. There are two forms, namely the surface map and the upper-air maps, of the basic weather map. Weather forecasting comprises of 5 steps as follow: 1st Step: Observation Meteorologists gather surface observations (every 3 hours) and upper air data (every 12 hours) using satellites and weather radars. Numerical weather predictions are analyzed through computers. 2nd Step: Collection and Transmission of Data Weather data is condensed into coded figures and transmitted via radio, telephone, and satellite to forecast centers 3rd Step: Plotting of Weather Data Weather observations are plotted on charts, decoding the data into symbols or numbers on weather maps. 4th Step: Analysis of Data Weather maps, satellite images, and radar imageries are analyzed to track weather patterns like wind directions, pressure systems, and rainfall. 5th Step: Formulation of Forecast Meteorologists review the data, determine the position of weather systems, and create forecasts based on their analysis.