After a gray and murky May, the weather rebounded in the month's last week, bringing some mid-summer-feeling temperatures in the 80s and 90s. Tuesday should also be warmer than average, with temperatures in the low 80s, according to CBS4 , a sign that snow is melting off mountain peaks. And it is coming fast---so fast that Barker Reservoir above Boulder Creek is spilling over the dam, causing fears for people's safety (via CBS4 ). On Sunday, Brandon Bowie, 25, of Indiana, fell into the Cache La Poudre River while tubing and has been missing since, according to the Fort Collins Coloradoan . Most of Colorado's rivers were flowing quickly Sunday with some at near-record flows for the date because of the warm weather, according to The Denver Post . Is global warming to blame? A U.S. Geological Survey report from last week indicates Colorado snowmelts are occurring two to three weeks earlier than they were in the late 1970s because of climate trends, according to the Post.