Is it possible to experience alcohol withdrawal in hours?

Usually not: Alcohol withdrawal usually takes place in 2-4 days, but as early as 24 hours, but not earlier normally.

Yes: Alcohol withdrawal can begin 6-12 hours after your last drink. The minor symptoms include tremors, insomnia, irritability, mild agitation, anorexia, nausea, vomiting, tension, anxiety, sweating, restlessness. More serious symptoms include hallucinations, tremors and delirium (delirium tremons). Alcohol withdrawal can be life threatening and merits an immediate trip to the er.