Dark Waters explores the relationship between disaster relief organizations and ethnic Mexican communities in the aftermath of flood disasters in the American West during the 1920 and 1930s.  It focuses on the American Red Cross and Cruz Azul  Mexicana (Mexican Blue Cross), two principal organizations that were on the ground after catastrophic flood disasters, setting up shelters, arranging hot meals, and nursing the ill and injured.  However, their approach towards relief varied due to race, class, language and citizenship.  The American Red Cross led by Euro-Americans espoused the principle of neutrality and refused to defy local customs and racial norms. However, rather than ensure equitable treatment of Mexican survivors, the Red Cross officials maintained separate relief camps, compensated relief workers with lower wages, and distributed less money for claims of life, injury and property.  Cruz Azul Mexicana, composed of Mexican women, worked closely with the Mexican Consulate Office and community organizations to assist destitute families during environmental disasters.  In the wake of flood disasters with Mexican victims and survivors, Cruz Azul sprang into action to assist the American Red Cross with language interpretation and emergency relief operations. To collect funds for disaster relief, Cruz Azul women organized fundraising events with music, dance and Hollywood star celebrities. Through their alliance with the Red Cross, I argue that Cruz Azul chapters achieved meaningful gains for Mexican communities by expanding the range of services offered and promoting social and political participation in local and national affairs.  My main research questions include: What kind of relationships did disaster relief organizations establish with ethnic Mexican communities? What kinds of mobilizations or responses took place outside of formal relief work? How do disaster relief efforts replicate, aggravate or rupture existing inequalities in cities and towns with ethnic Mexican communities?  How did ethnic Mexicans use disasters to contest and reimagine their relationship to the city and nation?