The 1996 Pacific hurricane season was below-normal in terms of tropical cyclone activity due to an ongoing La Niña, which also suppressed activity in the previous season. There were a total of nine storms named by the National Hurricane Center (NHC), of which five became hurricanes. Two of the hurricanes became a major hurricane, which is a Category 3 or stronger on the Saffir-Simpson scale. With an Accumulated cyclone energy (ACE) index of 53.9, the season ranks among the least intense Pacific hurricane seasons on record. It officially began May 15, 1996, in the eastern north Pacific and on June 1, 1996, in the central north Pacific. It ended on November 30, 1996. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean. The season slightly exceeded these bounds when tropical storm One-E formed on May 13.
Much of the season's activity was clustered near the coast of Southwest Mexico, with four hurricanes and one tropical storm making landfall along it. The most impactful were: Hurricane Alma, which was responsible for 20 deaths, and Hurricane Fausto, which left behind damage amounting to around $800,000 (1996 USD). Hurricane Douglas was the strongest storm of the season, reaching Category 4 intensity on the Saffir-Simpson Hurricane Scale. Douglas developed in the Caribbean Sea, within the Atlantic basin, as Hurricane Cesar, before crossing into the Pacific as a tropical storm. Another crossover storm was Atlantic Hurricane Dolly, which hit the Mexican state of Veracruz along the Gulf of Mexico and later entered the eastern Pacific as a tropical depression.
Seasonal summary
The season officially began on May 15 in Eastern Pacific and on June 1 in Central Pacific; both ended on November 30. This season was below average in activity due to an ongoing La Niña, which also suppressed activity in the previous season. In the eastern north Pacific, eleven tropical cyclones formed. Of these, four became hurricanes, one of which were major hurricanes because they reached Category 3 or higher on the Saffir-Simpson Hurricane Scale. The remainder were tropical storms. In addition, one Atlantic hurricane, Cesar, crossed into the Pacific as a tropical storm, at which time it was renamed Douglas. None of the systems in the eastern north Pacific crossed 140°W into the central Pacific. The last time that happened was in the 1979 season.
In the central Pacific, one tropical depression formed. In addition, a depression crossed the dateline from the western Pacific before dissipating in this basin. Neither of these systems reached tropical storm strength. In addition, data from the Joint Typhoon Warning Center, on September 1 Tropical Depression Rick crossed the International Dateline, entering into CPHC's area of responsibility; however, this storm was not included into CPHC database. The storm eventually became extratropical on September 3 over open waters.
In terms of the number of storms, the season was below average. Despite this, there were a large number of landfalls. During a ten-day span from June 23 to July 3, three tropical cyclones approached close to, or made landfall on, Mexico. In all, a record-setting four hurricanes (Alma, Boris, Fausto, and Hernan) struck the coastline.
The Accumulated Cyclone Energy (ACE) index for the 1996 Pacific hurricane season (Eastern Pacific and Central Pacific combined) as calculated by Colorado State University using data from the National Hurricane Center was 53.9 units, making this season a below-normal season. It is one of the lowest totals ever recorded, with only the 1977, 2010 and 2007 seasons having a lower ACE.
Systems
Unnamed tropical storm (One-E)
The season had an early start on May 13 when a tropical wave in the open ocean organized into Tropical Depression One-E. The depression moved west-northwest and strengthened into a tropical storm on May 14. On that day, the tropical storm reached its peak intensity, with maximum sustained winds at 50 mph (80 km/h) and a minimum central pressure of 1,000 hPa (29.53 inHg). Wind shear steadily weakened the cyclone until it dissipated early on May 17. This system was the only tropical storm to form in May during the period from 1992 to 1999.
This storm was not assigned a name because it was determined to be a tropical storm after the season was over. Subsequently, wind reports relayed from the US Coast Guard to the National Hurricane Center suggested that this cyclone was a tropical storm. This tropical cyclone impacted two ships. The first—called the True Blue—was near the fringes of the storm and escaped. The other—the trimaran Solar Wind—provided wind observations until communications with the vessel were lost after 0600 UTC on May 14. Despite a search by the US Coast Guard, the ship and its two-person crew were never found.
Tropical Depression Two-E
On May 15 an area of disturbed weather in the Intertropical Convergence Zone developed into a tropical depression. The disturbance was not readily traceable back to a tropical wave from the Atlantic. On its first day of its existence, Tropical Depression Two-E was a well-organized system with maximum sustained winds of 35 mph (56 km/h) and a minimum central pressure of 1,006 mbar (29.7 inHg). As it slowly moved west, Two-E experienced a few intermittent bursts of convection. However, the depression gradually became less organized during the remainder of its life. On May 18, the cyclone's organization deteriorated markedly until it dissipated the next morning.
Hurricane Alma
The origins of Alma is believed to be related to the tropical wave 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.
In anticipation for the storm, hurricane warnings were placed into effect along 175 mi (282 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 Michoacán state government sent five truckloads of bedding and medicines. In the Mexican states of Guerrero and Michoacán, the hurricane generated estimated wind gusts of up to 100 mph (160 km/h), and dropped large amounts of rainfall peaking at 19.09 in (485 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.
Hurricane Boris
Hurricane Boris originated from a tropical wave that moved off the west coast of Africa on June 8. The poorly organized wave tracked westward across the Atlantic Ocean and Caribbean Sea and entered the Pacific Ocean on June 23. The first signs of a circulation on satellite imagery appeared on June 26, centered about 250 miles (400 km) south of the Gulf of Tehuantepec. The system gained enough circulation definition and rainbands to acquire tropical depression status on June 27. The rate of intensification increased and the depression became a tropical storm on June 28. Boris reached hurricane intensity on June 28 and peaked with winds of 90 mph (140 km/h) and a central pressure of 979 mbar (28.9 inHg). It developed a ragged eye in the center. Boris made landfall on June 29 about midway between Lázaro Cárdenas and Acapulco. Boris then moved offshore after turning to the southwest and dissipated on July 1 while south of Puerto Vallarta.
Hurricane warnings were issued for southern Mexico due to Boris. The caused ten deaths. One person was killed in Tecpan. Nearby, three other people drowned and five fishers were missing. In Acapulco, a child was killed when a roof collapsed. Also, in Acapulco, strong surf pushed fishing boats against a sea wall. Trees were downed, and business signs were blown down. Streets were flooded to the level of the tires. Trees were knocked down. A total of about 10,000 people were left homeless, and at least 70 people were injured. Rain was heavy throughout the impacted region, with the highest totals in Guerrero. A total of 12.16 inches (309 mm) was recorded in Coyuca de Benítez. The highest total was 14.98 inches (380 mm) at Paso de San Antonio, to the east of the point of landfall. The heavy rain caused damaging floods on the Balsas River, which left at least 5000 homeless. In Tecpan, a countless number of homes were washed away. Winds went as high as 90 miles per hour (140 km/h). The storm flooded lobbies of hotels along the coast. Approximately 12 boats were sunk offshore. Tecpan bore the brunt of the storm, reporting heavy damage.
Tropical Storm Cristina
Cristina likely originated from area of thunderstorms that was affiliated with a tropical wave that had passed over Panama on June 29. By June 30, thunderstorm activity increased while located west the Pacific coast of Central America. At 1200 UTC July 1, as convective banding became organized, the National Hurricane Center initialed advisories Tropical Depression Five-E. At this time, the low located 300 miles (480 km) south of San Salvador, El Salvador. Quickly organizing, the depression was upgraded into Tropical Storm Cristina while 260 miles (420 km) south of Guatemala City, Guatemala. With warm water and low wind shear, Cristina strengthened to peak winds of 70 mph (110 km/h) and a minimum pressure of 991 mbar (hPa). Early on July 3, the center of Tropical Storm Cristina crossed the Mexican coast near Puerto Ángel at peak intensity. Within six hours, Cristina had weakened into a minimal tropical storm over the mountainous terrain of Mexico. By early July 3, the remnants of the tropical storm had completely dissipated.
On July 2, the Mexican government issued a tropical storm warning from the Mexico–Guatemala border to Punta Maldonado, Guerrero. Cristina was the third storm to hit the region in less than two weeks. Tropical Storm Cristina dropped extremely heavy precipitation over southern Mexico and over 1,350 sites received rain. Many areas received more than 10 in (250 mm) of rainfall and a peak of 15.12 in (384 mm) fell in San Pedro Tapanatepec. One fisherman drowned, another went missing, and another was found alive after their fishing boat sank off the coast of Oaxaca. Flash flooding and mudslides in Oaxaca killed five and in Guerrero at least seven people died. In the latter state, 51 communities were flooded, thus leaving 350 people homeless. In addition, 62 people were declared missing when eleven fishing boats were reported missing on July 2. On July 18, President Zedillo held meetings with the victims of Hurricane Boris and Cristina in Tecpan and Acapulco.
Tropical Depression Six-E
On July 4, a persistent area of thunderstorms organized into a tropical depression. Weak steering currents slowly moved it northwest. Easterly wind shear inhibited the development of the system. Despite the wind shear, Six-E was forecast to strengthen into a tropical storm, but it instead weakened to a swirl of clouds and advisories were ended on July 5. Tropical Depression Six-E dissipated on July 6. At its peak strength, Six-E had winds of 35 mph (56 km/h) and a central pressure of 1,003 mbar (29.6 inHg).