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Hurricane Alma (1996)
Encyclopedia
Hurricane Alma was the first of three consecutively named storms to make landfall on the Pacific coast of Mexico during a ten-day span. Alma was the third tropical cyclone
, first named storm and first hurricane of the 1996 Pacific hurricane season
. It is believed that the storm originated out of an Atlantic
tropical wave
which crossed Central America
in the middle of June. In warmer than average waters of the open Pacific
, it gradually organized and it was first designated as a tropical depression on June 20 before quickly intensifying to a tropical storm. Early on June 22 the storm was upgraded to a hurricane and subsequently reached peak intensity of 969 mb, a Category 2 on the Saffir-Simpson Hurricane Scale
. Alma made landfall on Mexico
's shoreline, but it soon moved back out over water and began to weaken. Alma had severe impact in Mexico. Twenty deaths were reported. Damage is unknown.
which spawned Tropical Storm Arthur
in the Atlantic
. Satellite imagery and upper–air observations indicated that the disturbance crossed Central America
during the middle of June, entering warming than average waters of the Pacific. Initially, the system was located within a sheared
environment, although it did not hinder development. The convection soon became aligned with the low–level center and during the overnight on June 20 it was designated as a tropical depression. The depression intensified and it was upgraded to Tropical Storm Alma later that day. The wind shear relaxed it was upgraded to a hurricane at early on July 22 while tracking generally northwest.
A mid–level trough
located near Baja California
and a mid- to-upper-level low over the southwest Gulf of Mexico
began to steer Alma northward towards the southwest coast of Mexico
, prior to reaching a peak intensity of 969 mb at 1200 UTC on June 23. Before long, the steering flow collapsed and the hurricane drifted further towards land. Later that day it made landfall near Lazaro Cardenas, although Alma quickly moved back over open water and meandered for about 36 hours. This made the hurricane the first of three consecutive storms to make landfall on, the Pacific coast of Mexico during a ten day span. It weakened to a tropical storm over land, before moving back to the open waters.
However, a small portion of the circulation of Alma was still over land, and thus it was severely disrupted by Mexico's high terrain. Alma was tracking slowly along a path roughly parallel to the coastline, it was further downgraded to a tropical depression on June 25. Alma remained weak and dissipated on June 27.
Alma was forecasted well, with errors well below long-term averages at the time. Despite this, tropical cyclone prediction models were a mixture of accurate and inaccurate, with the Aviation and GFDL models performing badly and the OFCI model performing well. The errors in dynamic models was attributed to a lack of data on upper-air conditions over the ocean southwest of the cyclone.
s were placed into effect along 175 mi (281.6 km) of coastline between the resorts of Zihuatenejo and Manzanillo. Hundreds of people were evacuated prior to the passage of the hurricane. Also, the Mexican government sent troops to the area to help with disaster relief, and the Michoacan
state government sent five truckloads of bedding and medicines. Prior to landfall, 14 inches of rain was expected.
In the Mexican states of Guerrero
and Michoacan
, the hurricane generated estimated wind gusts of up to 100 mph (160.9 km/h), and dropped large amounts of rainfall peaking at 19.09 in (484.9 mm) of rainfall just east of where it had made landfall. Also, there were reports of swells up to 12 ft (3.7 m) along the coast. Three people died in Lazaro Cardenas when their house collapsed. Alma ripped roofs off of some houses, downed power lines and uprooted numerous trees, Flooding for Alma left thousands homeless. Heavy rainfall resulted in major flooding in Puebla
, which killed 17 people. In all, 20 deaths were reported in Mexico. Damage is unknown, since the official report has no damage figures.
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...
, first named storm and first hurricane of the 1996 Pacific hurricane season
1996 Pacific hurricane season
The 1996 Pacific hurricane season was an event in tropical cyclone formation and the third least active Pacific hurricane season in recorded history, behind 1977 and 2010. It officially began May 15, 1996 in the eastern north Pacific and on June 1, 1996 in the central north Pacific. It ended on...
. It is believed that the storm originated out of an Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
tropical wave
Tropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
which crossed Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
in the middle of June. In warmer than average waters of the open Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, it gradually organized and it was first designated as a tropical depression on June 20 before quickly intensifying to a tropical storm. Early on June 22 the storm was upgraded to a hurricane and subsequently reached peak intensity of 969 mb, a Category 2 on the Saffir-Simpson Hurricane Scale
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
. Alma made landfall on Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
's shoreline, but it soon moved back out over water and began to weaken. Alma had severe impact in Mexico. Twenty deaths were reported. Damage is unknown.
Meteorological history
The origins of Alma is believed to be related to the tropical waveTropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
which spawned Tropical Storm Arthur
Tropical Storm Arthur (1996)
Tropical Storm Arthur caused minimal flooding in the Carolinas in mid-June 1996. The first tropical cyclone and named storm of the annual Atlantic hurricane season, Arthur originated from an area of increased convection east of the Bahamas on June 16. Gradually, the system increased in...
in the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. Satellite imagery and upper–air observations indicated that the disturbance crossed Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
during the middle of June, entering warming than average waters of the Pacific. Initially, the system was located within a sheared
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
environment, although it did not hinder development. The convection soon became aligned with the low–level center and during the overnight on June 20 it was designated as a tropical depression. The depression intensified and it was upgraded to Tropical Storm Alma later that day. The wind shear relaxed it was upgraded to a hurricane at early on July 22 while tracking generally northwest.
A mid–level trough
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...
located near Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
and a mid- to-upper-level low over the southwest Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
began to steer Alma northward towards the southwest coast of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, prior to reaching a peak intensity of 969 mb at 1200 UTC on June 23. Before long, the steering flow collapsed and the hurricane drifted further towards land. Later that day it made landfall near Lazaro Cardenas, although Alma quickly moved back over open water and meandered for about 36 hours. This made the hurricane the first of three consecutive storms to make landfall on, the Pacific coast of Mexico during a ten day span. It weakened to a tropical storm over land, before moving back to the open waters.
However, a small portion of the circulation of Alma was still over land, and thus it was severely disrupted by Mexico's high terrain. Alma was tracking slowly along a path roughly parallel to the coastline, it was further downgraded to a tropical depression on June 25. Alma remained weak and dissipated on June 27.
Alma was forecasted well, with errors well below long-term averages at the time. Despite this, tropical cyclone prediction models were a mixture of accurate and inaccurate, with the Aviation and GFDL models performing badly and the OFCI model performing well. The errors in dynamic models was attributed to a lack of data on upper-air conditions over the ocean southwest of the cyclone.
Preparations and Impact
In anticipation for the storm, hurricane warningTropical cyclone warnings and watches
Warnings and watches are two levels of alert issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate...
s were placed into effect along 175 mi (281.6 km) of coastline between the resorts of Zihuatenejo and Manzanillo. Hundreds of people were evacuated prior to the passage of the hurricane. Also, the Mexican government sent troops to the area to help with disaster relief, and the Michoacan
Michoacán
Michoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia...
state government sent five truckloads of bedding and medicines. Prior to landfall, 14 inches of rain was expected.
Guerrero
Guerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....
and Michoacan
Michoacán
Michoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia...
, the hurricane generated estimated wind gusts of up to 100 mph (160.9 km/h), and dropped large amounts of rainfall peaking at 19.09 in (484.9 mm) of rainfall just east of where it had made landfall. Also, there were reports of swells up to 12 ft (3.7 m) along the coast. Three people died in Lazaro Cardenas when their house collapsed. Alma ripped roofs off of some houses, downed power lines and uprooted numerous trees, Flooding for Alma left thousands homeless. Heavy rainfall resulted in major flooding in Puebla
Puebla, Puebla
The city and municipality of Puebla is the capital of the state of Puebla, and one of the five most important colonial cities in Mexico. Being a planned city, it is located to the east of Mexico City and west of Mexico's main port, Veracruz, on the main route between the two.The city was founded...
, which killed 17 people. In all, 20 deaths were reported in Mexico. Damage is unknown, since the official report has no damage figures.
See also
- Other tropical cyclones named Alma
- List of Pacific hurricanes