I also heard back from the Masters program around the 18th, and received funding information later in the mail. Since the initial email from SNRE, I received separate communications a few days later from Rackham (Graduate Division for most of University of Michigan I believe) and the head of the concentration within SNRE... so it's possible that it takes a few days for admissions decisions to go through the bureaucracy and pass on to the applicant. Best of luck!