lucrative drug corridor because of the large volume of trucks that pass through the area, and the multiple exploitable ports of entry. Nuevo Laredo is the base of Los Zetas, originally the armed wing of the Gulf Cartel; the two organizations separated in early 2010 and have been fighting for the control of the smuggling routes to the United States. As of 2012, Los Zetas are thought to be Mexico's largest criminal organization. Drug violence involving the Sinaloa and Gulf Cartels escalated in 2003, when the city was controlled by the Gulf Cartel. 2012 saw an unprecedented series of mass murder attacks in the city between the Sinaloa Cartel and Gulf Cartel on one side and Los Zetas on the other. Geography Nuevo Laredo is in the northern tip of Tamaulipas on the west end of the Rio Grande Plains. The Rio Grande is the only source that supplies its citizens with water. El Coyote Creek supplies Nuevo Laredo's only natural lake El Laguito (The Small Lake). The area consists of a few hills and flat land covered with grass, oak, and mesquite. Climate Nuevo Laredo features a semi-arid climate. Nuevo Laredo's weather is influenced by its proximity to the Chihuahuan Desert to the west, by the Sierra Madre Oriental mountains to the south and west, and by the Gulf of Mexico to the east. Much of the moisture from the Pacific is blocked by the Sierra Madre Oriental. Therefore, most of the moisture derives from the Gulf of Mexico. Its geographic location causes Nuevo Laredo's weather to range from long periods of heat to sudden violent storms in a short period of time. Nuevo Laredo is cold for Tamaulipas standards during winter, the average daytime highs are around and overnight lows around ; although it is rare for snow to fall in Nuevo Laredo, there was actually snow on the ground for a few hours on the morning of Christmas Day 2004. Nuevo Laredo experiences an average high temperature of about , and an average low of about during summer, and of rain per year. As Laredo sometimes undergoes drought, a water conservation ordinance was implemented in 2003. Government Nuevo Laredo is governed by an elected Cabildo, which is composed of the Presidente Municipal (Municipal President or Mayor), two Síndicos, and twenty Regidores. The PAN is in control of the city government. The Mayor is in charge of the