In October 1999, severe flooding affected portions of eastern Mexico and Central America. Rainfall in September preceded the primary event in Mexico, which moistened soils. On October 4, Tropical Depression Eleven developed in the Gulf of Mexico, which drew humidity from the gulf and the Pacific Ocean to produce torrential rainfall in mountainous regions of eastern Mexico, reaching in Jalacingo, Veracruz. This was the third-highest tropical cyclone-related rainfall total in Mexico from 1980–2006, and the event caused the highest rainfall related to tropical cyclones in Veracruz, Hidalgo, and Puebla. In some locations, the daily rainfall represented over 10% of the annual precipitation total. The heaviest rainfall occurred in mountainous regions that were the mouths of several rivers. A broad trough absorbed the depression on October 6, and rainfall continued for the next few days. Additional rainfall occurred in Tabasco state on October 18. The floods were estimated as a 1 in 67 year event in one location, although such floods are expected to affect eastern Mexico twice per century, the last time being 1944.
Throughout Mexico, the floods killed at least 379 people, according to the federal government, and as many as 600 according to relief agencies; the Centre for Research on the Epidemiology of Disasters later estimated there were 636 deaths, and damage in Mexico was estimated at $451.3 million (4.3 billion pesos). Nationwide, the floods damaged or destroyed 90,000 houses, which left about 500,000 people homeless. Flooding caused thousands of landslides, many in more populated areas than the flooding in 1944. The floods also caused 39 rivers to overflow, and the combination of floods and landslides destroyed bridges, houses, widespread crop fields, schools, and electrical networks. Impact was worst in Puebla, where damage totaled $240 million (2.1 billion pesos) and many roads were washed out. Landslides in the state killed 107 people in Teziutlán. Elsewhere in the country, the floods washed crocodiles into the streets of Villahermosa, the capital of Tabasco, and in Oaxaca, the rainfall occurred after an earthquake left thousands homeless. Flooding also extended into Central America in late September through early October, causing $40 million (385 million pesos) in crop damage and 70 deaths.
After the floods receded, Mexican President Ernesto Zedillo ordered the Department of National Defense to utilize all resources to assist the people affected by the floods. More than 94,000 people stayed at 896 shelters after being evacuated due to the floods. The federal government allocated $234 million (2.34 billion pesos) in relief, which was smaller than the damage total. Widespread medical teams assisted tens of thousands of homes, and due to prevention measures, there were no outbreaks of diseases. Roads and electrical systems were gradually restored, and students returned to school after repairs were made. Residents throughout Mexico sent supplies to the Mexican Red Cross, including 500 tons of food and water, and international agencies sent money and supplies to the flood victims.
Meteorological history
Beginning around September 10, heavy rainfall occurred sporadically in southern Mexico and into Central America, influenced by a broader storm system related to Hurricane Floyd. Toward the end of September, heavy rainfall occurred in the mountains of northeastern Mexico, which prompted officials to open flood gates. The rains occurred throughout Mexico for about two weeks before the worst of the precipitation began, and saturated soils before the heaviest rainfall in October.
On October 4, Tropical Depression Eleven developed in the Bay of Campeche about northeast of Veracruz, having originated from a tropical wave. Due to weak steering currents, the depression moved erratically, initially to the south and later to the west-northwest. It failed to intensify due to a surface trough over the central and eastern Gulf of Mexico, connected to a cold front. While the depression was drifting, it produced large areas of convection over eastern Mexico, aided by high humidity from the gulf and from the Pacific Ocean. On October 6, the circulation was absorbed into the trough, although rainfall continued to occur through October 9. A week later, Hurricane Irene affected southern Mexico with strong rains. Additional rainfall occurred on October 18 in Tabasco, causing further flooding; the waters in the state began receding on October 28. The wet conditions in eastern Mexico, occurring at the same time as hot, dry conditions elsewhere in the country, were possibly related to La Niña conditions.
Due to easterly wind shear and the convection along the storm's western periphery, the tropical depression dropped heavy rainfall in the states of Puebla, Tabasco, Hidalgo, and Veracruz, peaking at in Jalacingo, Veracruz. This was the highest rainfall total in Veracruz from 1981 to 2010; statewide record peaks were also reported in Puebla and Hidalgo. The depression was the third wettest tropical cyclone in Mexico from 1983 to 2006, after Hurricane Wilma in 2005 and Tropical Storm Frances in 1998. The heaviest of the rainfall occurred along the Sierra Madre Oriental, which is a mountain range in eastern Mexico and the source for several regionally important rivers. Tuxpan, Veracruz recorded 6.2 in (157.7 mm) in a 24‑hour period on October 4, which was greater than the average October rainfall there and was about one-ninth of the annual total. A station in Hidalgo reported 4.02 in (102 mm) on October 4, which was also greater than the average October rainfall and was about one-eighth of the annual total. The return period was estimated as high as a 1 in 67 year event at Xicotepec, Puebla, and it was estimated that such floods in Mexico occur only twice per century; similar floods occurred in September 1944 in the same region, although the area was less populated then.
Impact
Mexico
Across eastern Mexico, the heavy rainfall caused mudslides and floods, which damaged or destroyed 90,000 houses, and damaged or destroyed about 3,088,000 acres (1,250,000 hectares) of crop fields; thousands of livestock were also killed. The floods affected 819 Municipalities of Mexico in 17 states and the federal district, leaving about 500,000 people homeless, of whom half were in Tabasco and Veracruz states. Several ports were closed due to the floods. Although power lines were downed, most electrical systems were not damaged, and power was quickly restored within a week in most areas. A total of 39 rivers overflowed, which washed away bridges, roads, dams, and some entire houses, and there were thousands of landslides, mostly in unpopulated areas. Collectively, 28 federal highways and 300 rural roads were closed or damaged. The federal highway network sustained damage in 1,237 locations as a result of 1,164 landslides or mudslides and 28 damaged bridges. Damage was estimated at $451.3 million (4.3 billion pesos).
The death toll was 61 as of October 6, and a day later it reached about 250. The Mexican government reported 341 deaths on October 13, excluding victims in a landslide in Acalama, Puebla, and the total reached 379 by October 28. However, non-government agencies reported 500 deaths in Mexico by October 9, and as many as 600 as of mid-November. The International Disaster Database, published by the Centre for Research on the Epidemiology of Disasters, reported 636 deaths from the floods. The high death toll, in comparison to similar floods in 1944, was due to more landslides and flooding in more populated areas. About 500,000 people were injured.
In Tulancingo, Hidalgo, a nearby river flooded 6,750 houses and buildings, reaching 3 ft (1 m) in some places and affecting about half of the town. Elsewhere in Hidalgo, the rains collapsed a mine in San Salvador, burying seven people. A total of 8,342 people had to evacuate to 75 shelters. The combination of washouts and landslides damaged 168 rural roads and 36 state highways, causing $3.85 million (38 million pesos) in damage. Fourteen people died statewide. In the state of Tabasco, rivers reached their highest stage in about 40 years, affecting about 75% of the state by October 8. About of flooding was reported in some places, which washed crocodiles into streets in the capital city, Villahermosa. Statewide, over 58,000 people had to evacuate due to flooding, including portions of Villahermosa, where 90,955 people were injured. In the city, 1,600 prisoners had to be transported after a jail was flooded. Nine people died in the state. Additional floods caused further flooding later in October.
Flooding was considered worst in Puebla, and were the worst floods in about 400 years, according to newspaper reports. A total of 21,342 people evacuated their houses to 116 shelters, mostly in the state's northern portion. The floods affected 16,511 houses and 199 schools. In Teziutlán, with a population of about 50,000, it is estimated the city received nearly half of its annual rainfall in about three days. Nine entire communities became isolated due to the floods, and the small village of Patla sustained heavy damage after the Necaxa River changed its course closer to the town. Widespread landslides occurred, including over 80 in Teziutlán alone; one mudslide there destroyed 80 houses. Some of the landslides occurred along rivers and produced new lakes, but 85% of these broke within the first year. Population growth, primarily in Teziutlán and Zaragoza, occurred in landslide-prone areas along mountains. Along Sierra Norte de Puebla, deforestation contributed to additional landslides. A landslide covered the Zacatepec River near Zempoala, creating a natural dam and a small lake. Mudslides buried at least 16 people at a school in Pantepec, and a deforested hill caused a landslide in the Indigenous village of Acalama, which covered up to 170 people. Most had fled to a church that was also covered, and it is estimated that only 30 people survived in the village. Statewide, 263 people were killed, including 107 in Teziutlán who were buried by mudslides, becoming the worst disaster in the history of the town. In the village of Tetela de Ocampo, 31 people died. In Puebla, 30,000 people were injured, and 81 municipalities sustained damage, with statewide damage estimated at about $240 million (2.1 billion pesos).
In Veracruz, 124 people were killed in the event, including three in a rescue helicopter crash. About 23,500 people statewide had to evacuate to emergency shelters in 452 communities. The governor declared the state as a disaster zone after 13 rivers exceeded their banks, and two entire villages were washed away. A total of 75,135 people were injured in Veracruz, about one third of whom became homeless due to the floods. In rural areas, 77,123 people lost power. Statewide, 11 bridges were damaged, and 22 portions along the Poza Rica-Veracruz highway was damaged. In Zaragoza, the floods destroyed 91% of the year's crops.
There were six deaths in Chiapas during the flood event. In the state, four dams reached near record water levels. In Oaxaca, the rains left thousands homeless and disrupted work to clean up after an earthquake a week prior. The floods displaced 800 families, and six people died in the state. The floods spread as far west as Jalisco, where 3 roads were destroyed and 12 municipalities were affected. In nearby Michoacán, 5,000 people were injured.
Central America