Typhoon? Hurricane? Cyclone? Here's the difference - CBS News
STRENGTH: A storm gets a name and is considered a tropical storm at 39 mph ( 63 kph). It becomes a hurricane, typhoon, tropical cyclone. Hurricanes, typhoons and tropical cyclones all refer to storms in which the winds reach more than 74 miles per hour. The difference in the names refers to the. Hurricanes are tropical cyclones that form in warm waters near the equator. Typhoons are a tropical storm that forms in the west Pacific and.
First described by Japanese meteorologist Fujiwhara Sakuhei inthe Fujiwhara effect occurs when two hurricanes get within miles km of each other.
Once they are within that distance, they will rotate around a point directly between their centers, like dancers circling each other. If the storms are about the same size, the interaction might simply alter their trajectories before they break apart.
On the other hand, if one storm is much smaller than the other, then the larger storm might absorb the smaller one once they get close enough.
Meteorologists classify tropical cyclones depending on their wind speed. Once the winds reach 74 mph km per hourthe storm graduates to hurricane status. Usually, that is the wind speed necessary for an eye to form in its center.
Meteorologists sort hurricanes into five categories depending on their maximum sustained wind speed. Versions of the Saffir-Simpson Scale are used officially in the U. Terrifying Category 5 storms have petered out at sea without doing any human damage at all.
Hurricanes and the Natural World When we think of hurricane damage, we tend to think of the way these storms impact people and human infrastructure—and for good reason.
Hurricanes, Typhoons, and Tropical Cyclones by Evelyn Dubey on Prezi
But even when hurricanes barely touch humans, they can wreak havoc on the natural world. A hurricane can leave its mark by rearranging geography. Hurricanes change coastlines, uprooting trees with their powerful winds and moving earth with the force of water.
When Hurricane Agnes hit the Chesapeake Bay init reconfigured the hydrology of the area, eroding away the mouths of tributaries to the Bay and transporting huge amounts of sediment upstream. In the tropics, new islands can be formed by the accumulation of coral skeletons, and sometimes entire blocks of reef are displaced by the hurricane and deposited on top of the shallow near-shore zone of the reef.
These crops were toppled by Typhoon Sarika in in Hainan, China. When Hurricane Agnes hit the Chesapeake Bay, it decimated the population of oysters and soft-shelled clams in that estuarine ecosystem. In the Chesapeake Bay, Agnes severely stressed organisms that lived only in a specific salinity range and lacked the ability to move into a less affected area. Hurricanes may also destroy coastal wetlands Source 51reduce the population of submerged aquatic plants—which shelter and feed many aquatic species—and depress the reproduction of fish whose eggs and larvae are washed away.
Coral reefs are particularly prone to hurricane damage because they are shallow-water ecosystems in the tropics.
The damage begins with brute-force destruction dealt by high-intensity waves and debris in the water. Hurricanes smash and sweep away corals, and reefs that run perpendicular to the prevailing winds and waves bear the brunt of the impact. When the storm cleared, 80 percent of the corals from that reef had disappeared entirely. The most vulnerable coral species are those with long-delicate branches, one notable example in the Atlantic being the endangered staghorn coral, Acropora cervicornis.
In enclosed bays with limited circulation, lowered salinity can kill the corals or stress them by causing them to expel the photosynthetic algae zooxanthellae that feed them. Corals like this staghorn coral, Acropora cervicornis, are particularly susceptible to fragmenting during a powerful hurricane.
Flickr user Via Tsuji The results of a hurricane impact on a reef can be wide-ranging and long-lasting. When Hurricane Allen hit Jamaican reefs init destroyed, overturned and fragmented corals.
But for the fragile Acropora cervicornis, the deaths continued. Instead of reviving, the staghorn coral population collapsed. In the Caribbean overall, coral populations have a lot of trouble bouncing back after hurricanes, particularly when the ecosystem is already suffering from other human impacts like over-fishing and pollution.
Following the year of impact, the rate of coral cover decline is 6 percent a year—higher than the normal decline rate of corals.
Because corals play a foundational role in the reef ecosystem, their disappearance can make life much harder for other organisms that feed on them or use them for shelter.
Hurricanes, typhoons and cyclones: What's the difference? - BBC News
When hurricanes make landfall, they damage land ecosystems too. In a tropical rainforest, a hurricane can uproot trees, snap their trunks, or denude them of leaves, as was the case in Puerto Rico after Hurricane Hugo in and Hurricane Maria in Because trees, like corals, are foundational to the ecosystem in which they live, dead trees can be bad news.
Still, an impact does alter a forest, notably by clearing space for grasses and faster-sprouting trees. No place emerges from a hurricane completely unscathed. At least 38 people died, trees were leveled, and houses reduced to shambles. Here, storm surge sends ships into the streets of Providence, Rhode Island. Although awe-inspiring, they are all too often tragic when they come ashore.
But the deadliest storms are not always those that are strongest at landfall. Much depends on us humans: Direct Damage Hurricanes kill far fewer people today than they did in the past. When the Galveston Hurricane hit Texas init claimed 8, lives. The Galveston Hurricane has the highest death toll of any hurricane in U. In comparison, Hurricane Katrina inone of the worst natural disasters in the U. The bad news is that we are still very vulnerable to hurricanes.
Hurricanes, typhoons and cyclones: What's the difference?
Hurricanes are among the deadliest of natural disasters. In Southeast Asia, Pacific hurricanes killed people a year on average between and Note, however, that averages conceal enormous variability. A single hurricane, the Great Bhola Cyclone, killed almost half a million people when it struck Bangladesh in When Hurricane Katrina hit the US init accounted for more than 40 percent of the hurricane-related deaths in the entire year period.
Overall, about one percent of the storms that hit the U. A map shows flood depth after Hurricane Katrina. NOAA Hurricanes kill in multiple different ways. Wind is interestingly responsible for only eight percent of storm-related deaths, at least in the U.
This wall of water piles higher and higher as the storm enters the shallow water near the shore, and by the time the hurricane hits, it may flood the land with anywhere from four to more than 18 feet of water. Damage depends on the timing of landfall—particularly if a hurricane hits during high tide—and the topography of the coast. The greater the area of shallow water approaching the coast, the larger the storm surge. If the tide is high when the hurricane hits, that also boosts the water level.
For Katrina, during which levee failures exacerbated the danger of the storm surge, as well as for other deadly U.
For instance, Hurricane Camille in and Hurricane Agnes in claimed most lives through rainfall-induced floods and mudslides, which are also a serious danger in Japan. Meanwhile, 20 of the 72 deaths caused by Hurricane Sandy were wind-related, resulting from falling trees. The breaking levees caused considerable damage in the area around New Orleans, Louisiana after Hurricane Katrina hit in September NOAA Besides inflicting loss of life, hurricanes also cause loss of livelihood for those in their paths, by destroying communities and damaging property.
On average, hurricane damages cost the U. In Southeast Asia, the annual cost averaged 3. Again, most of the damage is usually concentrated in a few especially devastating storms. Across the entire world since the yeartropical cyclones have incurred the loss of more thanhuman lives and more than billion dollars in property damage.
Most of that cost comes immediately upon impact. After the Fact Hurricanes destabilize lives. The survivors of a hurricane might have lost loved ones or have no home to go back to. They may be newly deprived of the community relationships and support structures—not to mention the resources—they need to get back on their feet.
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Homelessness and displacement, food shortages, and lack of access to health care can make recovery a slow road. In the wake of Hurricane Sandy debris and destruction can be seen in and around the houses in Breezy Point, N.
Courtade The aftermath of a hurricane often has consequences for public health. After Agnes incontaminated shellfish made people sick. More seriously, the aftermath of a hurricane often includes an outbreak of infectious and sometimes deadly disease, particularly in crowded areas with low immunization rates, limited access to clean water, and poor sanitation. When people must continue to stay in crowded and underserved shelters, epidemics can occur even months after the hurricane actually hits.
For example, outbreaks of typhoid and the measles occurred five months after Hurricanes David and Fredrick hit the Dominican Republic in Floodwaters are also great places for bacteria to spread. Luckily it was an isolated incident. When Hurricane Flora hit Haiti init gave mosquitoes new breeding grounds and forced the survivors outside where they could be bitten, contributing to more than 75, cases of malaria. A similar outbreak occurred soon after Hurricane Mitch hit the Caribbean in Along with physical ailments like injury and disease, hurricanes also leave invisible psychological and emotional damages in their wakes.
Part of the problem is in the timing. People generally do a good job of rushing in to support survivors right after the disaster strikes, but some psychological hurts make themselves known over time and once support ebbs, survivors may feel abandoned.
Preparedness and Response There is no way for humans to stop a hurricane, and sometimes people foolishly ignore the risks, even when they are well publicized. Track and intensity predictions for Hurricane Katrina were accurate enough, for example, that evacuation could have been ordered two or three days in advance. Because the evacuation was well organized and roads were ready to accommodate the outflow, the evacuation saved many lives.
Afterwards, however, supplies had trouble getting into the affected area, and people had trouble getting out of it, exacerbating the death toll.
Carribean Islands, are a bit trickier to evacuate. In the aftermath of Maria inthe entire island of Puerto Rico was devasted and the aid response was slow. A month after the hurricane many on the island were still without food, clean water, and power—circumstances that many call a humanitarian crisis. By contrast, after Hurricane Sandy hit New York inresponders made food and water immediately available.
After an impact, it is critical to have a well-organized and effective emergency response. US Navy, Petty Officer 3rd Class Dana Denice Legg But well before the event, we need to pay attention to the other major player in a hurricane impact—the landscape that gets hit.
Infrastructure can be designed with hurricanes in mind on a much larger scale than just boarding up windows before a storm hits although that is an important precaution to take. Seawalls and artificial levees must be built strong and high enough to withstand storm surge.
An entire city on microgrids would have a significantly reduced risk of widespread power outages during a hurricane. Hurricane Katrina provides a case study. Between and a canal leading inland from the Gulf of Mexico was built.
In the half century prior to Hurricane Katrina, Louisiana lost 1, square miles of its wetlands to development. Similar patterns of wetland destruction occur in other hurricane-vulnerable locations across the globe, like Thailand. Estuaries serve as important buffers against storm damage.
When coastal waters rise during a storm, also called storm surge, a marsh estuary can easily absorb the extra water with minimal damage to the environment. NOAA Why do wetlands matter? Quite simply, they are the front line of protection against hurricanes.
Wetlands sponge up the energy of a hurricane from the moment it hits land. They also act like a strainer for the storm surge, decreasing its force and height. Each square mile of wetland, in fact, reduced the height of the storm surge by three inches when Hurricane Andrew hit Florida in Overall, each square mile of wetland loss corresponds to a loss of 8.
In the ocean, coral reefs can play a similarly vital role in protecting against large waves. All we have to do is preserve these important natural barriers. Hurricanes and Climate Change We know that climate can affect hurricane formation. Scientists also recently discovered that hurricanes in the Atlantic intensify more rapidly now than when compared to 30 years ago. If they are north of the equator they rotate counterclockwise. If they are south, they rotate clockwise. The Atlantic and central Pacific hurricane seasons are June 1 through Nov.
May 15 to Nov. The cyclone season in the south Pacific and Australia runs from November to April. The northwestern Pacific where Typhoon Haiyan has just hit. A normal year there involves 27 named storms.
Haiyan is the 28th named storm and there has already been a 29th. By comparison the Atlantic averages 11 named storms a year and this year there have been 12, none of them causing major problems.
The lists are maintained by the World Meteorological Organization; the names are ones that are familiar in each region. Names are taken off the list and replaced to avoid confusion if a hurricane causes a lot of damage or deaths. For example, Katrina was retired after it devastated New Orleans in The Philippines has its own naming system, so Typhoon Haiyan is also being called Yolanda.
During an El Nino - when the central Pacific is warming - there are fewer Atlantic storms. El Ninos shift where storms form, but not the number, for the northwest Pacific and the southwest Pacific.
The central Pacific gets more storms during El Nino and the year after. This year has neither an El Nino nor its opposite, a La Nina. It is a neutral year.