From 28 to 30 October 2007, exceptional rainfall fell in the Grijalva River Basin, in Chiapas and Tabasco, Mexico, producing huge runoff and flooding in about 70% of the Tabasco flatlands. More than 1 million people were affected, mostly in the city of Villahermosa. In southeastern Mexico, flooding damages have increased in the last decades, due to population growth and human settlements developing in areas prone to flooding. A preliminary analysis is made of the causes of the disaster and of the possible courses of action that could be taken to prevent similar situations in the future. The hydrometeorological occurrence of the phenomenon is reviewed, and the operation and management of dams and other flood control system components, including forecast and alert procedures, are assessed. Recommendations are made on integrated flood management, joint operational policies of infrastructure, a territorial ordinance plan, forecast needs, social participation, training, and information dissemination among the population and stakeholders.
Extreme temperatures and heat wave trends in five cities within the Sonoran Desert region (e.g., Tucson and Phoenix, Arizona, in the United States and Ciudad Obregon and San Luis Rio Colorado, Sonora; and Mexicali, Baja California, in Mexico) and one city within the Mojave Desert region (e.g., Las Vegas, Nevada) were assessed using field data collected from 1950 to 2014. Instead of being selected by watershed, the cities were selected because they are part of the same arid climatic region. The data were analyzed for maximum temperature increases and the trends were confirmed statistically using Spearman's nonparametric test. Temperature trends were correlated with the mortality information related with extreme heat events in the region. The results showed a clear trend of increasing maximum temperatures during the months of June, July, and August for five of the six cities and statically confirmed using Spearman's rho values. Las Vegas was the only city where the temperature increase was not confirmed using Spearman's test, probably because it is geographically located outside of the Sonoran Desert or because of its proximity to the Hoover Dam. The relationship between mortality and temperature was analyzed for the cities of Mexicali, Mexico and Phoenix. Arizona.
Due to its geographical location and interaction with the two largest oceans, Mexico's climate is strongly influenced by various climatic oscillations. Therefore, association studies between climatic indices and Mexico's climate have scientific and practical importance. Teleconnection patterns have been reported between summer precipitation and various climate oscillations. For the Atlantic Multidecadal Oscillation (AMO), results are not totally coincident, and modulation of El Niño Southern Oscillation (ENSO) effects has not been explored. Correlation analyses between the AMO and Oceanic El Niño Index (ONI)3.4 with summer precipitation (June–September) at individual 203 weather stations in Mexican coastal zones were carried out, and average precipitation was compared according to AMO phases and their combinations with ENSO events. With AMO + , it tends to rain more in the northern Yucatan Peninsula, from Chiapas to Jalisco, and in the southern California Peninsula; with AMO− in Tamaulipas, Sonora and northern California Peninsula. The AMO modulates ENSO effects; ONI correlations pattern strengthens with AMO+. El Niño summers are less dry with AMO− on the Atlantic coast, Sonora and northern California Peninsula; on the Pacific coast, alternating bands are observed. With AMO − , La Niña summers tend to be wetter toward the south with AMO+ and toward the north with AMO−. These changes can be related to variations in the surface and low-level wind regimes previously reported in the literature.
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