Typhoon Ivan (1997)
Encyclopedia
Typhoon Ivan was an intense tropical cyclone
that existed simultaneously with another storm of the same intensity. Forming out of an area of disturbed weather on October 13, Ivan gradually intensified into a typhoon as it tracked steadily to the west-northwest. On October 15, the storm underwent rapid intensification
and reached an intensity corresponding to Category 5 status on the Saffir–Simpson Hurricane Scale. Late on October 17, Ivan reached its peak strength with winds of 295 km/h (185 mph) and a barometric pressure of 905 hPa (mbar). Shortly thereafter, the typhoon began to weaken as it approached the Philippines. Ivan eventually made landfall in northern Luzon
with winds of 220 km/h (140 mph) on October 20 before weakening to a tropical storm the next day. The storm then curved northeastward and became extratropical
on October 25 and dissipating the following day.
Although Ivan was a powerful storm at landfall, its effects were relatively minor compared to the storms' intensity; however, 14 people were killed during the storm and two others were listed as missing. Agricultural industries sustained the most severe damage, as thousands of animals drowned in the storm. Total damage was estimated at $9.6 million (1997 USD; $13.1 million 2009 USD). A total of 1,779 homes were destroyed, 13,771 others were damaged and 4,600 hectares of farmland were flooded by the storm.
during the first week of October 1997. Two equatorial troughs
, one in the Northern Hemisphere
and one in the Southern Hemisphere
developed from this system. Three resultant areas of low pressure
formed; one in the Southern Hemisphere developed into Cyclone Lusi on October 8, and two north of the equator steadily tracked westward. The eastern low developed into Typhoon Joan, while the western cyclone became the system that would intensify into Typhoon Ivan. Situated in an environment without significant convective activity
, this system initially struggled to become organized. However, the disturbance began to mature, and by October 11, the Joint Typhoon Warning Center
(JTWC) discovered a low-level circulation center, prompting the issuance of a Tropical Cyclone Formation Alert
the following day.
The system quickly tracked toward the west-northwest at a forward speed of 33 km/h (21 mph). The JTWC issued their first advisory on the storm early on October 13, designating it Tropical Depression 27W. Around this time, the Japan Meteorological Agency
(JMA) also classified the cyclone as a tropical depression.
Convective banding features
developed late on October 13. The JTWC upgraded the depression to a tropical storm and gave it the name Ivan. Early the next day, the JMA also upgraded Ivan to a tropical storm. Later on October 14, Ivan passed roughly 100 km (65 mi) south of Guam
and subsequently intensified. Several hours afterwards, the JMA upgraded Ivan to a typhoon. During a 24-hour span, Ivan's winds increased from 120 km/h (75 mph) to 270 km/h (165 mph), making it a Category 5 super typhoon, the eighth of the season. Late on October 17, Ivan attained its peak intensity with winds of 295 km/h (185 mph) and an official barometric pressure of 905 hPa (mbar). However, the JTWC reported an unofficial pressure of 872 hPa (mbar), which would tie Ivan for the second strongest tropical cyclone worldwide with Typhoons Gay, Joan and Keith.
Due to the storm's proximity to Typhoon Joan, forecast models anticipated Ivan to re-curve before reaching the Philippines; however, the storm maintained its track and did not take the northward turn until impacting the country. The typhoon began to slow and weaken, and on October 20, its center made landfall in extreme northern Luzon with winds of 220 km/h (140 mph). After emerging into the Luzon Strait
, Ivan turned to the north-northeast and weakened to a tropical storm. On October 22, the storm briefly re-attained typhoon status before accelerating in forward speed. The system steadily weakened and the JTWC issued their final advisory on the storm on October 24. The JMA continued to monitor Ivan as a tropical cyclone for another day before classifying it as extratropical. The remnants of the powerful typhoon eventually dissipated on October 26.
as Ivan approached. Power was shut off prior to the storm to reduce the risk of electrocution. Four flights were cancelled in Taiwan, Hong Kong, and the Philippines due to the storm. Residents in Taiwan were advised to take precautions for Typhoon Ivan, though autumn typhoons are rare in the island. Vessels were urged to stay at port due to rough seas throughout the Philippines. Disaster agencies were put on high alert; relief supplies were then stockpiled, the navy was placed on standby, and military search and rescue vehicles were prepped.
On October 20, Ivan made landfall in the northern Philippines, producing torrential rains that triggered waist-deep flooding in localized areas. Severe crop losses were reported throughout northern Luzon
. One person drowned in floodwaters in Cagayan
. Elsewhere in the country, two other people drowned in floodwaters. Numerous power lines and trees were downed throughout the region, rain-triggered landslides blocked several roads. Throughout the country, a total of 14 people were killed and two others were listed as missing. Poultry farms and fisheries sustained significant damage; an estimated $3.6 million in losses resulted from lost stocks in the two businesses. Several thousand animals drowned during the storm. Total damage was estimated at $9.6 million (1997 USD; $13.1 million 2009 USD). A total of 1,779 homes were destroyed, 13,771 others were damaged and 4,600 hectares of croplands were inundated by Typhoon Ivan. Rainfall from the storm was considered to be helpful as the area impacted had been suffering from below average rainfall for several months. Minor damage was also reported in the Marshall Islands
. The island of Tiyan recorded 5.26 in (133.6 mm) of precipitation, contributing to above-average rainfall during the month of October.
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
that existed simultaneously with another storm of the same intensity. Forming out of an area of disturbed weather on October 13, Ivan gradually intensified into a typhoon as it tracked steadily to the west-northwest. On October 15, the storm underwent rapid intensification
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...
and reached an intensity corresponding to Category 5 status on the Saffir–Simpson Hurricane Scale. Late on October 17, Ivan reached its peak strength with winds of 295 km/h (185 mph) and a barometric pressure of 905 hPa (mbar). Shortly thereafter, the typhoon began to weaken as it approached the Philippines. Ivan eventually made landfall in northern Luzon
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
with winds of 220 km/h (140 mph) on October 20 before weakening to a tropical storm the next day. The storm then curved northeastward and became extratropical
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
on October 25 and dissipating the following day.
Although Ivan was a powerful storm at landfall, its effects were relatively minor compared to the storms' intensity; however, 14 people were killed during the storm and two others were listed as missing. Agricultural industries sustained the most severe damage, as thousands of animals drowned in the storm. Total damage was estimated at $9.6 million (1997 USD; $13.1 million 2009 USD). A total of 1,779 homes were destroyed, 13,771 others were damaged and 4,600 hectares of farmland were flooded by the storm.
Meteorological history
Typhoon Ivan originated from an area of disturbed weather near the equatorEquator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
during the first week of October 1997. Two equatorial troughs
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
, one in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
and one in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
developed from this system. Three resultant areas of low pressure
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
formed; one in the Southern Hemisphere developed into Cyclone Lusi on October 8, and two north of the equator steadily tracked westward. The eastern low developed into Typhoon Joan, while the western cyclone became the system that would intensify into Typhoon Ivan. Situated in an environment without significant convective activity
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
, this system initially struggled to become organized. However, the disturbance began to mature, and by October 11, the Joint Typhoon Warning Center
Joint Typhoon Warning Center
The Joint Typhoon Warning Center is a joint United States Navy – United States Air Force task force located at the Naval Maritime Forecast Center in Pearl Harbor, Hawaii...
(JTWC) discovered a low-level circulation center, prompting the issuance of a Tropical Cyclone Formation Alert
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Naval Maritime Forecast Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone forming from a tropical disturbance that has been...
the following day.
The system quickly tracked toward the west-northwest at a forward speed of 33 km/h (21 mph). The JTWC issued their first advisory on the storm early on October 13, designating it Tropical Depression 27W. Around this time, the Japan Meteorological Agency
Japan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...
(JMA) also classified the cyclone as a tropical depression.
Convective banding features
Rainband
A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as...
developed late on October 13. The JTWC upgraded the depression to a tropical storm and gave it the name Ivan. Early the next day, the JMA also upgraded Ivan to a tropical storm. Later on October 14, Ivan passed roughly 100 km (65 mi) south of Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
and subsequently intensified. Several hours afterwards, the JMA upgraded Ivan to a typhoon. During a 24-hour span, Ivan's winds increased from 120 km/h (75 mph) to 270 km/h (165 mph), making it a Category 5 super typhoon, the eighth of the season. Late on October 17, Ivan attained its peak intensity with winds of 295 km/h (185 mph) and an official barometric pressure of 905 hPa (mbar). However, the JTWC reported an unofficial pressure of 872 hPa (mbar), which would tie Ivan for the second strongest tropical cyclone worldwide with Typhoons Gay, Joan and Keith.
Due to the storm's proximity to Typhoon Joan, forecast models anticipated Ivan to re-curve before reaching the Philippines; however, the storm maintained its track and did not take the northward turn until impacting the country. The typhoon began to slow and weaken, and on October 20, its center made landfall in extreme northern Luzon with winds of 220 km/h (140 mph). After emerging into the Luzon Strait
Luzon Strait
The Luzon Strait is the strait between the island country of Taiwan and Luzon island of the Philippines. The strait thereby connects the Philippine Sea to the South China Sea in the western Pacific Ocean....
, Ivan turned to the north-northeast and weakened to a tropical storm. On October 22, the storm briefly re-attained typhoon status before accelerating in forward speed. The system steadily weakened and the JTWC issued their final advisory on the storm on October 24. The JMA continued to monitor Ivan as a tropical cyclone for another day before classifying it as extratropical. The remnants of the powerful typhoon eventually dissipated on October 26.
Preparations and impact
Thousands of people evacuated from northern areas of the PhilippinesPhilippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
as Ivan approached. Power was shut off prior to the storm to reduce the risk of electrocution. Four flights were cancelled in Taiwan, Hong Kong, and the Philippines due to the storm. Residents in Taiwan were advised to take precautions for Typhoon Ivan, though autumn typhoons are rare in the island. Vessels were urged to stay at port due to rough seas throughout the Philippines. Disaster agencies were put on high alert; relief supplies were then stockpiled, the navy was placed on standby, and military search and rescue vehicles were prepped.
On October 20, Ivan made landfall in the northern Philippines, producing torrential rains that triggered waist-deep flooding in localized areas. Severe crop losses were reported throughout northern Luzon
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
. One person drowned in floodwaters in Cagayan
Cagayan
Cagayan , the "Land of Smiling Beauty", is a province of the Philippines in the Cagayan Valley region in Luzon. Its capital is Tuguegarao City and is located at the northeastern corner of the island of Luzon. Cagayan also includes the Babuyan Islands to the north. The province borders Ilocos Norte...
. Elsewhere in the country, two other people drowned in floodwaters. Numerous power lines and trees were downed throughout the region, rain-triggered landslides blocked several roads. Throughout the country, a total of 14 people were killed and two others were listed as missing. Poultry farms and fisheries sustained significant damage; an estimated $3.6 million in losses resulted from lost stocks in the two businesses. Several thousand animals drowned during the storm. Total damage was estimated at $9.6 million (1997 USD; $13.1 million 2009 USD). A total of 1,779 homes were destroyed, 13,771 others were damaged and 4,600 hectares of croplands were inundated by Typhoon Ivan. Rainfall from the storm was considered to be helpful as the area impacted had been suffering from below average rainfall for several months. Minor damage was also reported in the Marshall Islands
Marshall Islands
The Republic of the Marshall Islands , , is a Micronesian nation of atolls and islands in the middle of the Pacific Ocean, just west of the International Date Line and just north of the Equator. As of July 2011 the population was 67,182...
. The island of Tiyan recorded 5.26 in (133.6 mm) of precipitation, contributing to above-average rainfall during the month of October.
See also
- 1997 Pacific typhoon season1997 Pacific typhoon seasonThe 1997 Pacific typhoon season has no official bounds; it ran year-round in 1997, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern...
- Typhoons in the PhilippinesTyphoons in the PhilippinesTyphoons in the Philippines refer in general to tropical cyclones that enter the Philippine area of responsibility and affect the Philippines. Locally they are called bagyo...