Hydrometeorological Hazards PDF

Hydrometeorological and Coastal Processes and Hazards BIG IDEA: Hydrometeorological phenomena cause hazards and may accelerate coastal processes. The hazards may be mitigated through government and private or personal initiative.  Coastal Processes and Hazards The Philippin...

Hydrometeorological and Coastal Processes and Hazards BIG IDEA: Hydrometeorological phenomena cause hazards and may accelerate coastal processes. The hazards may be mitigated through government and private or personal initiative.  Coastal Processes and Hazards The Philippines has a total of 7,641 islands and has one of the longest coastlines in the world, approximately 36,289 km.  Coastal Processes 1. Erosion 2. Submersion 3. Salt intrusion TYPHOON  WHAT IS TYPHOON? Tropical Cyclones that develops in the north-western part of the Pacific Ocean. In the Philippines, tropical cyclones (typhoons) are called bagyo. The term bagyo, a Filipino word meaning typhoon arose after a 1911 storm in the city of Baguio had a record rainfall of 46 inches within a 24-hour period.  WHAT IS TYPHOON, HURRICANE AND TROPICAL CYCLONE? The terms "hurricane" and "typhoon" are regionally specific names for a strong "tropical cyclone". A tropical cyclone is the generic term for a non-frontal synoptic scale low-pressure system over tropical or sub-tropical waters with organized convection (i.e. thunderstorm activity) and definite cyclonic surface wind circulation  WHAT IS TYPHOON, HURRICANE AND TROPICAL CYCLONE? If winds reach 33 m/s (64 km, 74 mph), then they are called: "hurricane" (the North Atlantic Ocean, the Northeast Pacific Ocean east of the dateline, or the South Pacific Ocean east of 160E) "typhoon" (the Northwest Pacific Ocean west of the dateline) "severe tropical cyclone" or "Category 3 cyclone" and above (the Southwest Pacific Ocean west of 160°E or Southeast Indian Ocean east of 90°E) "very severe cyclonic storm" (the North Indian Ocean) "tropical cyclone" (the Southwest Indian Ocean) CATEGORIES OF TYPHOON  CATEGORIES OF TYPHOON CATEGORY 1 TROPICAL DEPRESSION SUSTAINS WINDS BETWEEN 119 AND 153 KM/HOUR (KM/H). IT IS THE FIRST NOTABLE STAGE IN THE FORMATION OF A TYPHOON.  CATEGORIES OF TYPHOON CATEGORY 2 TROPICAL STORM (TS) HAS WINDS BETWEEN 154 AND 177 KM/H. -A TROPICAL STORM IS A SYSTEM OF INTENSE THUNDERSTORMS THAT PROGRESSIVELY INTENSIFIES.  CATEGORIES OF TYPHOON CATEGORY 3 STRONG TYPHOON A STRONG TYPHOON IS A SYSTEM OF LOW PRESSURE AND INTENSE WINDS (BETWEEN 178 AND 209 KM/H). (MAEMI-SOUTH KOREA)  CATEGORIES OF TYPHOON CATEGORY 4 INTENSE TYPHOON AN INTENSE TYPHOON SUSTAINS HIGH WINDS OF 210 TO 249 KM/H AND IS CLASSIFIED AS A CATEGORY-5 STORM, WHICH CARRIES THE HIGHEST ELEMENT OF RISK.  CATEGORIES OF TYPHOON CATEGORY 5 VIOLENT TYPHOON A VIOLENT TYPHOON IS CHARACTERIZED BY WINDS EXCEEDING 249 KM/H. (TYPHOON HAIYAN)  7300 1901 1593 1359 1410 1268 30+ LIST OF PHILIPPINE HISTORICAL TYPHOON (1970-2011) NAMES OF TYPHOONS MARKED THE PHILIPPINE HISTORY Milenyo (Xangsane) - 2006 Frank (Fengshen) - 2008 Ondoy (Ketsana) - 2009 Juan (Megi) - 2010 Bebeng (Aere) - 2011 Ambo (Mawar) - 2012 Yolanda (Haiyan) - 2013 Glenda (Rammasun) - 2014 Lando (Koppu) - 2015 Ompong (Mangkhut) - 2018 MONSOONS  NORTHEAST MONSOON (AMIHAN) It is characterized by moderate temperatures, little or no rainfall in the central and western part of Luzon and Visayas, and a prevailing wind from the east. On the east coast of Luzon it brings drizzling rainfall and squalls. The effect on Mindanao relatively less than in the northern part of the country. As a rule of thumb, the Philippines' amihan weather pattern begins sometime in November or December and ends sometime in May or June. There may, however, be wide variations from year to year.  SOUTHWEST MONSOON (HABAGAT) The Philippines' habagat weather pattern begins sometime in June or July and ends sometime in September or October. The Philippines experiences the west or southwest wind; south west monsoon. The habagat season is characterized by hot and humid weather, frequent heavy rainfall, and a prevailing wind from the western parts. STAGES OF TYPHOON FOUR STAGES OF TYPHOON FORMATIVE STAGE IMMATURE STAGE MATURE STAGE DECAYING STAGE  FORMATIVE STAGE The incipient stage when the tropical cyclone form in waves and in shear lines of pre-existing disturbances and winds usually remain below the typhoon force.  IMMATURE STAGE The deepening stage of the cyclone during which it continues to deepen until the lowest central pressure and the maximum wind intensity are reached. However, intensification does not usually take place since some have been known to die down even though the winds has attained typhoon force.  MATURE STAGE The stage of maturity of the tropical cyclones where the areas of circulation expands while the surface pressure no longer falls and no increase in maximum winds speed can be observed which may last for a week.  DECAYING STAGE The dissipating stage of the tropical cyclone where the surface pressure rises and the area affected by the cyclones diminishes in size as it recurves or dissipate due to friction and lack of moisture over continents or when colder and drier air enters through when they go poleward. STRUCTURE OF TYPHOON  THE EYE The hurricane's center is a relatively calm, generally clear area of sinking air and light winds that usually do not exceed 15 mph (24 km/h) and is typically 20-40 miles (32-64 km) across. An eye will usually develop when the maximum sustained wind speeds go above 74 mph (119 km/h) and is the calmest part of the storm  THE EYEWALL Where the strong wind gets as close as it can is the eyewall. The eyewall consists of a ring of tall thunderstorms that produce heavy rains and usually the strongest winds. Changes in the structure of the eye and eyewall can cause changes in the wind speed, which is an indicator of the storm intensity. The eye can grow or shrink in size, and double (concentric) eyewalls can form.  RAINBANDS Curved bands of clouds and thunderstorms that trail away from the eye wall in a spiral fashion. These bands are capable of producing heavy bursts of rain and wind, as well as tornadoes. There are sometimes gaps in between spiral rainbands where no rain or wind is found. EFFECTS OF TYPHOONS Strong wind Tornadoes Rainfall Flood Possible Storm surge TYPHOON MITIGATION  TYPHOON MITIGATION ACTIONS BEFORE: Increase Knowledge, Determine Risk, Safeguard, Plan General All-Hazard Actions: Determine the disaster risks in your locale and the hazards that accompany them. Increase your knowledge about the emergency warning signals and alert notifications used in your community. Instruct family members how to shut off water, gas and electricity to your house. Make the necessary property preparations to reduce the damage from the hazard. Acquire a backup generator in case of a prolonged power failure. Check into insurance (property, health, life, and hazard type). Make the necessary financial arrangements in case of a sudden evacuation and power outage that shuts down local ATMs and banks.  TYPHOON MITIGATION Organize important documents and records and store them in a portable lock box or safe-deposit box. Perform home inventory videotaping and store tape in a portable lock box or safe-deposit box. Develop an Emergency Communication Plan with evacuation plan and ask an out-of-state person to serve as the "family contact". Assemble a shelter-in-place Emergency Supplies Kit. Assemble a mobile Emergency Supplies Kit that can serve as a “grab and go” bag. Get a family member trained in first aid and CPR. Make the necessary preparations and arrangements for pets, seniors, and the disabled. Familiarize yourself with the emergency plans of your family member's employment building, school, day care center, or nursing home.  TYPHOON MITIGATION Hazard Specific Actions: Know the duration of the hurricane season. It starts on June 1 and runs through November 30. Check flashlights and radios. Make sure you have batteries. Check trees and shrubbery, and remove limbs that could damage your house or utility lines. Plan an evacuation route and learn safe routes inland. Make arrangements for family pets because some emergency shelters may not allow pets.  TYPHOON MITIGATION ACTIONS DURING: Safety Basics, Evacuation, Shelter in Place Hurricane Watch (conditions within 24-36 hours): Listen to battery-operated radio for progress reports; check emergency supplies. Fuel car. Bring in outdoor objects. Secure buildings by closing and boarding up windows. Remove outside antennas. Turn refrigerator and freezer to coldest settings. Store drinking water in clean bathtubs, jugs, and bottles. Moor boat securely or move to a designated safe place; anchor trailer to ground. Review evacuation plan.  TYPHOON MITIGATION Hurricane Warning (conditions expected in 24 hours or less): Listen to radio for instructions. Tie down mobile home and evacuate immediately. Store valuables in waterproof container Avoid elevators. If at home: Stay inside, away from anything glass. Keep a supply of batteries and flashlights. Avoid open flames as a source of light. If power is lost, turn off major appliances to reduce power surge. If evacuation is necessary: leave ASAP, avoiding flooded roads and washed-out bridges. Secure home by unplugging appliances and turning off electricity and the main water valve. If time permits, elevate furniture to protect it from flooding. Bring pre-assembled emergency supplies and warm clothing. Take blankets and sleeping bags to a shelter and leave immediately.  TYPHOON MITIGATION ACTIONS AFTER: Get Disaster Relief, Clean-up, Salvage Stay tuned to radio for information, returning home only when authorities advise it is safe to do so. Help injured or trapped persons and give first aid where appropriate. Avoid loose or dangling power lines and report them to the power company or fire department. Beware of snakes, insects, and animals driven to higher ground by flood water. Open windows and doors to ventilate and dry your home. Check refrigerated foods for spoilage. Take pictures of the damage for insurance claims. Drive only if necessary and avoid flooded roads and washed-out bridges. Use telephones only for emergency calls. DESTRUCTIVE WAVES DESTRUCTIVE WAVES TSUNAMI TIDAL WAVES STORM SURGE TSUNAMI  TSUNAMI These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become a tsunami.  TSUNAMI Most tsunamis –about 80 percent–happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common. SIGNS OF TSUNAMI  SIGNS OF TSUNAMI Severe ground shaking from local earthquakes may cause tsunamis. As a tsunami approaches shoreline, water may recede from the coast, exposing the ocean floor, reefs and fish. Abnormal ocean activity, a wall of water, and an approaching tsunami create a loud "roaring" sound similar to that of a train or jet aircraft.  WARNING SIGNS OF TSUNAMI An earthquake is a natural tsunami warning. If you feel a strong quake do not stay in a place where you are exposed to a tsunami. If you hear of an earthquake be aware of the possibility of a tsunami and listen to the radio or television for additional information. Remember that an earthquake can trigger killer waves thousands of miles across the ocean many hours after the event generated a tsunami. Witnesses have reported that an approaching tsunami is sometimes preceded by a noticeable fall or rise in the water level. If you see the ocean receding unusually rapidly or far it's a good sign that a big wave is on its way. Go to high ground immediately.  WARNING SIGNS OF TSUNAMI Many people were killed by the Indian Ocean tsunami because they went down to the beach to view the retreating ocean exposing the seafloor. Experts believe that a receding ocean may give people as much as five minutes' warning to evacuate the area. Remember that a tsunami is a series of waves and that the first wave may not be the most dangerous. The danger from a tsunami can last for several hours after the arrival of the first wave. A tsunami wave train may come as a series of surges that are five minutes to an hour apart. The cycle may be marked by a repeated retreat and advance of the ocean. Stay out of danger until you hear it is safe. TIDAL WAVE  TIDAL WAVE A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth on the ocean STORM SURGE  STORM SURGE Storm surge is the abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide. The surge is caused primarily by a storm’s winds pushing water onshore. The amplitude of the storm surge at any given location depends on the orientation of the coast line with the storm track; the intensity, size, and speed of the storm; and the local bathymetry. CAUSES OF STORM SURGE  CAUSES OF STORM SURGE The wind circulation around the eye of a hurricane The hurricane reaches shallow waters near the coast, the vertical circulation in the ocean becomes disrupted by the ocean bottom. Storm surge occurs where winds are blowing onshore. The highest surge tends to occur near the “radius of maximum winds,” or where the strongest winds of the hurricane occur. WATER COMPOSITION OF TOTAL WATER LEVEL WATER COMPOSITION OF TOTAL WATER LEVEL Tides - When the tide is combined with the storm surge, it is called the storm tide. Waves - Breaking waves contribute to the water level rise through wave runup and wave setup. Wave runup occurs when a wave breaks and the water is propelled onto the beach. Freshwater - Input Heavy rainfall ahead of a hurricane can cause river levels to rise well inland from the coast. Once all this water flows downriver and reaches the coast, local water levels especially near deltas and in bays will rise.  TOTAL WATER LEVEL = STORM SURGE + TIDES + WAVES + FRESHWATER STORM SURGE MITIGATION  STORM SURGE MITIGATION Tide Station - measure the variation in water level along the coast. Since tidal cycles are predictable, storm surge can be calculated by subtracting what the water level would have been in the absence of the storm from the measured water level. Pros: Available in real time Generally located in areas sheltered from waves and are able to measure “still water” Traditionally the most reliable way of measuring surge Cons: Limited number of stations along the coast, so there is often no real-time validation of storm surge in the most vulnerable areas Often fail at the height of an event due to loss of electrical power or damage STORM SURGE MITIGATION  STORM SURGE MITIGATION High water marks - are lines found on trees and structures marking the highest elevation of the water surface for a flood event, created by foam, seeds, or other debris. Survey crews are deployed after a storm to locate and record reliable high-water marks, usually through GPS methods. Pros: Traditionally the best method for capturing the highest surge from an event Cons: Are not available in real time Are perishable, so surveys need to be conducted as soon as possible after a storm Can be subjective Generally, include the effects of wave runup and setup, and only a small percentage represent “still water” STORM SURGE MITIGATION  STORM SURGE MITIGATION Pressure sensors - from the Geological Survey are temporary barometric pressure sensors that provide information about storm surge duration, times of arrival and retreat, and maximum depths. The sensors are installed around posts and other structures before the arrival of a hurricane. Pros: Are able to provide timing information that cannot be obtained from high water marks Can be deployed ahead of a storm at the locations of the highest expected surge Cons: Information from the sensors is not available in real time Can include the effects of waves, which will provide an overestimation of the storm surge height May be difficult to recover the instruments after a storm STORM SURGE MITIGATION FLOOD  FLOOD Flooding is an overflowing of water onto land that is normally dry. Floods can happen during heavy rains, when ocean waves come on shore, when snow melts too fast, or when dams or levees break. Flooding may happen with only a few inches of water, or it may cover a house to the rooftop. They can occur quickly or over a long period and may last days, weeks, or longer. Floods are the most common and widespread of all weather-related natural disasters.  FLASH FLOOD Flash floods are the most dangerous kind of floods, because they combine the destructive power of a flood with incredible speed and unpredictability. Flash floods occur when excessive water fills normally dry creeks or river beds along with currently flowing creeks and rivers, causing rapid rises of water in a short amount of time. They can happen with little or no warning.  ALERT IN IDENTIFYING FLOOD FLOOD WATCH: Flash flooding or flooding is possible within the designated watch area - be alert. FLASH FLOOD or FLOOD WARNING: Flash flooding or flooding has been reported or is imminent - take necessary precautions at once! Get to higher ground! URBAN and SMALL STREAM ADVISORY: Flooding of small streams, streets and low-lying areas, such as railroad underpasses and urban storm drains is occurring. FLASH FLOOD or FLOOD STATEMENT: Follow-up information regarding a flash flood/flood event.  TYPES OF FLOOD RIVER FLOOD - occurs when water levels rise over the top of river banks due to excessive rain from tropical systems making landfall, persistent thunderstorms over the same area for extended periods of time, combined rainfall and snowmelt, or an ice jam.  TYPES OF FLOOD COASTAL FLOOD - the inundation of land areas along the coast, is caused by higher than average high tide and worsened by heavy rainfall and onshore winds (i.e., wind blowing landward from the ocean).  TYPES OF FLOOD INLAND FLOODING - occurs when moderate precipitation accumulates over several days, intense precipitation falls over a short period, or a river overflows because of an ice or debris jam or dam or levee failure.  TYPES OF FLOOD FLASH FLOOD - is caused by heavy or excessive rainfall in a short period of time, generally less than six hours. Flash floods are usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them. FLOOD MITIGATION  FLOOD MITIGATION There are steps that you can take to prepare yourself and mitigate against damages. 1. The first thing you can do is know your risk, and we have information on risk. 2. Next, you should create an emergency communications plan and build an emergency kit to ensure you and your family are prepared for a flood. 3. As part of having a plan, we also encourage you to consider your coverage. A flood insurance policy can protect your home, property, or business from the financial damages of flooding. Most homeowner’s insurance does not cover damage from flooding.  FLOOD MITIGATION In addition to these steps, there are also small flood proofing measures that you can take to help prevent, or minimize the impact of flooding to your home and its contents. A few examples include: Elevate your furnace, water heater and electric panel in your home, if you live in a high flood risk area. Install "check valves" to prevent flood water from backing up into the drains of your home. When practical, homeowners can construct barriers (such as sandbagging) to stop flood water from entering your home. Seal walls in your basement with waterproofing compounds. TORNADO  TORNADO / TWISTER Tornadoes are vertical funnels of rapidly spinning air. Their winds may top 250 miles (400 kilometers) an hour and can clear a pathway a mile (1.6 kilometers) wide and 50 miles (80 kilometers) long. Twisters are born in thunderstorms and are often accompanied by hail. Giant, persistent thunderstorms called supercells spawn the most destructive tornadoes.  TORNADO FACTS A tornado forms when changes in wind speed and direction create a horizontal spinning effect within a storm cell. This effect is then tipped vertical by rising air moving up through the thunderclouds. The meteorological factors that drive tornadoes make them more likely at some times than at others. They occur more often in late afternoon, when thunderstorms are common, and are more prevalent in spring and summer. However, tornadoes can and do form at any time of the day and year. Tornadoes' distinctive funnel clouds are actually transparent. They become visible when water droplets pulled from a storm's moist air condense or when dust and debris are taken up.  CAUSE OF TORNADO The most violent tornadoes come from supercells, large thunderstorms that have winds already in rotation. About one in a thousand storms becomes a supercell, and one in five or six supercells spawns off a tornado. Supercells are storms usually, but not necessarily, thunderstorms that contain updrafts that rotate about a vertical axis. This rotation is derived from shear in the environmental wind field (that is, a change in wind direction and / or speed with height) surrounding the storm as it begins to grow. CLASSIFICATION OF TORNADO  CLASSIFICATION OF TORNADO Multivortex (multiple-vortex) tornadoes contain two or more small, intense subvortices orbiting the center of the larger tornado circulation. These vortices may form and die within a few seconds, sometimes appearing to train through the same part of the tornado one after another. They can happen in all sorts of tornado sizes, from huge "wedge" tornadoes to narrow "rope" tornadoes.  CLASSIFICATION OF TORNADO Waterspout is a tornado over water--usually meaning non-supercell tornadoes over water. Although waterspouts are always tornadoes by definition; they don't officially count in tornado records unless they hit land. They are smaller and weaker than the most intense Great Plains tornadoes, but still can be quite dangerous. Waterspouts can overturn boats, damage larger ships, do significant damage when hitting land, and kill people.  CLASSIFICATION OF TORNADO Landspout is storm-chaser slang for a non-supercell tornado. So-called "landspouts" resemble waterspouts in that way, and also in their typically small size and weakness compared to the most intense tornadoes. But "landspouts" are tornadoes by definition; and they are capable of doing significant damage and killing people.  CLASSIFICATION OF TORNADO Gustnado is a small and usually weak whirlwind which forms as an eddy in thunderstorm outflows. They do not connect with any cloud-base rotation and are not tornadoes. But because gustnadoes often have a spinning dust cloud at ground level, they are sometimes wrongly reported as tornadoes. Gustnadoes can do minor damage (e.g., break windows and tree limbs, overturn trash cans and toss lawn furniture), and should be avoided.  CLASSIFICATION OF TORNADO Dust devil is a small, rapidly rotating wind that is made visible by the dust, dirt or debris it picks up. Also called a whirlwind, it develops best on clear, dry, hot afternoons. TORNADO MITIGATION  TORNADO MITIGATION IF YOU ARE UNDER A TORNADO WARNING, FIND SAFE SHELTER RIGHT AWAY If you can safely get to a sturdy building, then do so immediately. Go to a safe room, basement, or storm cellar. If you are in a building with no basement, then get to a small interior room on the lowest level. Stay away from windows, doors, and outside walls. Do not get under an overpass or bridge. You’re safer in a low, flat location. Watch out for flying debris that can cause injury or death. Use your arms to protect your head and neck.  TORNADO MITIGATION HOW TO STAY SAFE WHEN A TORNADO THREATENS Prepare NOW ○ Know the signs of a tornado, including a rotating, funnel-shaped cloud; an approaching cloud of debris; or a loud roar—similar to a freight train. ○ Pay attention to weather reports. Meteorologists can predict when conditions might be right for a tornado. ○ Identify and practice going to a safe shelter in the event of high winds, such as a safe room built. The next best protection is a small, interior, windowless room on the lowest level of a sturdy building.  TORNADO MITIGATION Survive DURING ○ Immediately go to a safe location that you identified. ○ Take additional cover by shielding your head and neck with your arms and putting materials such as furniture and blankets around you. ○ Listen to Weather Radio, or local alerting systems for current emergency information and instructions. ○ Do not try to outrun a tornado in a vehicle. ○ If you are in a car or outdoors and cannot get to a building, cover your head and neck with your arms and cover your body with a coat or blanket, if possible.  TORNADO MITIGATION Be Safe AFTER ○ Keep listening to Weather Radio, and local authorities for updated information. ○ If you are trapped, cover your mouth with a cloth or mask to avoid breathing dust. Try to send a text, bang on a pipe or wall, or use a whistle instead of shouting. ○ Stay clear of fallen power lines or broken utility lines. ○ Do not enter damaged buildings until you are told that they are safe. ○ Save your phone calls for emergencies. Phone systems are often down or busy after a disaster. Use text messaging or social media to communicate with family and friends. ○ Be careful during clean-up. Wear thick-soled shoes, long pants, and work gloves. EL NIÑO & LA NIÑA  EL NIÑO AND LA NIÑA El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific (approximately between the International Date Line and 120 degrees West).  EL NIÑO AND LA NIÑA La Niña is sometimes referred to as the cold phase of ENSO and El Niño as the warm phase of ENSO. These deviations from normal surface temperatures can have large-scale impacts not only on ocean processes, but also on global weather and climate. El Niño and La Niña episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña. EFFECTS OF LA NIÑA  EFFECTS OF LA NIÑA Increased Rainfall Catastrophic Floods Drier Than Normal Conditions Increased Commercial Fishing Affects the Climate Patterns Affects Weather Cycles Economic Problems Around the Globe EFFECTS OF LA NIÑA EFFECTS OF EL NIÑO EFFECTS OF EL NIÑO EFFECTS OF EL NIÑO  NEXT TOPIC: FIRE HAZARDS