Hurricane Alex was the first tropical cyclone of the 2010 Atlantic hurricane season, and a rare June Atlantic hurricane. Originating from an area of disturbed weather on June 25, 2010, it slowly developed in the western Caribbean Sea and struck Belize as a strong tropical storm. After entering the Gulf of Mexico, Alex became very large and encountered conditions favorable for gradual development. Early on June 30, the cyclone attained hurricane status as it approached northeastern Mexico, the first June hurricane in the Atlantic basin since Hurricane Allison in 1995, and the storm rapidly intensified just off the coast of Tamaulipas. Alex made landfall near Soto la Marina as a Category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale. Alex rapidly weakened after landfall, with the storm losing its tropical status on July 2, before fully dissipating on July 6.
Alex caused the deaths of at least 51 people along its path, and produced over $1.5 billion (2010 USD) in damage. The precursor of the hurricane produced substantial rainfall across the Greater Antilles, causing one death in the Dominican Republic. Fourteen people were killed in Central America as a result of flooding during the first landfall of Alex. In Mexico, the storm's outer rainbands killed three people in Acapulco, one person in Oaxaca, and another in Chiapas. At its final landfall, Alex caused at least fifteen deaths in Nuevo León, eight in Coahuila, six in Guanajuato, and one in both Tamaulipas and San Luis Potosí; an additional twenty persons were reported missing.
Alex triggered widespread power outages throughout northeastern Mexico and southern Texas. Damage was most evident in the Monterrey metropolitan area, which faced what Nuevo León governor Rodrigo Medina de la Cruz described as, "the worst weather phenomenon in its history." Following Alex's final landfall, a state of emergency was declared for most of Nuevo León, portions of Tamaulipas, and Texas. Widespread flooding from the storm affected 500,000 people throughout northeast Mexico, and ruined over of crops in the region, equivalent to 11% of the region's total farmland.
Meteorological history
The weather system from which Hurricane Alex developed was first discernible as a disturbance in the Intertropical Convergence Zone (ITCZ) over the central Atlantic, on June 17. Over the next few days, most of the disturbance's associated thunderstorm activity was embedded within the ITCZ. The National Hurricane Center (NHC) first mentioned the system as a candidate for tropical cyclone formation on June 20, while it was crossing the Windward Islands into the southeastern Caribbean Sea; at the time, some upper-level wind shear was present, leading to conditions only marginally favorable for development. The system moved through the Caribbean, and on June 21, it developed to the extent that the NHC assessed a 50% chance of development into a tropical depression within 48 hours. The next day, however, the feature deteriorated, as thunderstorm activity spread across the Greater Antilles, although the upper-level regime remained favorable for eventual redevelopment.
On June 24, a low-level circulation had gradually become better established to the south of Jamaica, although it was displaced from its poorly organized convection. By 18:00 UTC, a surface low-pressure area had formed about to the northeast of Cabo Gracias a Dios, Nicaragua, but due to a lack of persistent thunderstorm activity, it was not yet considered a tropical cyclone. Later that day, convection increased over the center of circulation, and atmospheric pressures dropped across the region. Late on June 25, Hurricane Hunters verified the development of a surface low pressure area, which, combined with the increase of thunderstorm activity, indicated the system was a tropical depression. Accordingly, the cyclone was classified as Tropical Depression One at 22:00 UTC, while located about to the east-southeast of Chetumal, Quintana Roo. After the end of the hurricane season, the National Hurricane Center revised their analysis and estimated that the system had actually become a tropical depression at around 18:00 UTC. At the time of its formation, the depression was moving to the west-northwest, steered by a high pressure system over the northern Gulf of Mexico. An anticyclone positioned over the storm created an environment of minimal wind shear, and the depression quickly intensified. At 09:00 UTC on June 26, the system obtained tropical storm status and was given the name Alex.
As Tropical Storm Alex progressed through the western Caribbean Sea towards the Yucatán Peninsula, it developed a large field of clouds accompanied by well-established outflow throughout its circulation. Its inner structure was initially disorganized, although by late on June 26, it became better defined. At about 21:00 UTC, as the tropical storm approached the Belize coast, a Hurricane Hunters flight reported winds of ; early on June 27, Alex made landfall just north of Belize City at this intensity. Upon moving ashore, an area of convection increased over the center, and the convection initially became better defined as it crossed the Yucatán Peninsula. While most tropical cyclones weaken and become disorganized after landfall, Alex seemed to become stronger when viewed on radar and satellite imagery—the National Hurricane Center noted in one of its forecast discussions that the cyclone's structure more closely resembled a hurricane than a deteriorating storm. Still, after enough time over land, convective activity markedly decreased. Operationally, Alex was downgraded to a tropical depression as it approached the peninsula's western coastline; however post-analysis determined that Alex remained a minimal tropical storm. Late on June 27, the storm emerged into the Gulf of Mexico with a large overall convective structure but little thunderstorm activity near the center due to the interaction with land.
When Alex was still located over the Yucatán Peninsula, the NHC remarked upon the potential for significant strengthening. Because of low wind shear and very warm water temperatures in the Gulf of Mexico, the possibility existed that Alex could intensify into a major hurricane—a Category 3 storm on the Saffir-Simpson Hurricane Wind Scale—before its next landfall. Early on June 28, thunderstorm activity had reformed over the center, but over the following day, the combination of dry air, increasing wind shear and slightly cooler water temperatures prevented significant convection from developing over the center. At the same time, Alex was moving slowly off the northwest coast of the Yucatán Peninsula, and the environment's conditions became more favorable for intensification as the tropical storm tracked away from the coast. The circulation envelope of Alex remained very large, and by June 29, the storm's rainbands covered the entire western half of the Gulf of Mexico; rainfall was reported along the Texas and Louisiana coasts, even while the center was still several hundred miles offshore. The tropical storm continued to strengthen, and based on reports from Hurricane Hunters, it is estimated that Alex attained Category 1 hurricane status at 03:00 UTC on June 30, about southeast of Brownsville, Texas.
Upon becoming a hurricane, Alex was located in a moist, low shear environment, which led to steady intensification on June 30. The pressure continued to fall—a sign of an intensifying cyclone—with a more rapid drop occurring that afternoon and evening. The hurricane strengthened into a Category 2 storm late on June 30, as it approached the northeastern Mexican coast. At 02:00 UTC on July 1, Alex made landfall at peak strength, with maximum sustained winds of and an unusually low central pressure of in the municipality of Soto la Marina in the Mexican state of Tamaulipas. Operationally, the National Hurricane Center had the landfall intensity estimate as , gusts of and a of when it struck the Mexican coast. Several hours after moving ashore, the storm weakened to Category 1 status, and its structure began to deteriorate. However, deep convection persisted around the center. By 12:00 UTC, Alex had weakened into a tropical storm; by 00:00 UTC July 2, the Sierra Madre Oriental disrupted Alex's core, causing the storm to weaken into a tropical depression. Soon afterward, the storm's low-level circulation center dissipated over San Luis Potosí. However, the interaction with the mountain range caused orographic lift on the eastern side of the storm after the low-level circulation center had ceased to exist, producing torrential rainfall throughout northern and central Mexico. Following the dissipation of Alex, divergence at the 200 mb atmospheric pressure level (approximately at of altitude), a ridge of high pressure located over southern Texas, and Alex's residual moisture interacted to produce intense convection over Nuevo León, Tamaulipas and Coahuila for the next 72 hours. Alex's mid-level circulation persisted for another several days, with the remnants turning northeastward and slowly moving towards Texas. On July 6, Alex's remnants dissipated near the border of southwestern Texas.
Preparations
Caribbean Immediately after the storm formed on June 25, a tropical storm warning was issued for the entire east coast of Quintana Roo on Mexico's Yucatán Peninsula. Shortly thereafter, the tropical storm warning was extended to include the east coast of Belize. Late on June 25, the Government of Honduras issued a tropical storm warning for the islands of Roatan, Guanaja and Utila. A tropical storm watch was also issued from Limón to the border with Guatemala.
Western Gulf Coast
As Alex neared hurricane strength on the evening of June 28, a hurricane warning was issued for the coast of Texas south of Baffin Bay to the mouth of the Rio Grande. The Mexican government also issued a hurricane warning from the Rio Grande south to La Cruz. A tropical storm warning was posted for coastal Texas from Baffin Bay northward to Port O'Connor. Governor of Texas Rick Perry declared a state of disaster in 19 counties and ordered the deployment of Texas Military Forces personnel (including 80 citizen-soldiers of the Texas State Guard Medical Brigade) to the Rio Grande Valley. President Barack Obama also declared a state of emergency, freeing federal funds for 25 counties in Texas.
On June 29, authorities began evacuations of residents of coastal areas in the Tamaulipas municipalities of Soto la Marina, Matamoros and San Fernando municipalities. On June 30, the state's civil defense agency and education secretary announced that schools would be closed throughout the state during the storm. Thirteen shelters were opened in Reynosa, twenty-two in Matamoros, and ten in San Fernando; a total of 3,000 people sought protection from the storm in the three municipalities. Throughout the state, 20,000 people were asked to evacuate to safer areas. Nuevo León schools were also ordered to be closed for at least 24 hours; the Universidad Regiomontana, Universidad de Monterrey and Universidad Autónoma de Nuevo León followed suit. In Monterrey, mandatory evacuations alongside the Santa Catarina River were ordered, as well as the evacuation of 5,000 families in the highlands of the city. Throughout the state, a total of 90 shelters were opened. Coahuila did not close its schools, expecting Alex to reach the state as a tropical depression or weaker, but asked its schools to not take attendance.