According to my friend Shauna Brenneman at the Union, the whistle is powered by the university’s hot-water system, and it’s both manually and automatically operated. Automatic: a timer sets the whistle off for seven to 10 seconds one hour before sunset each day, calling boats back to shore. Manual: when the UWPD’s Lake Rescue and Safety team decides that severe weather is imminent — due to forecast information for the National Weather Service or online data or just the visual cues of seeing thunderheads and lightning over the lake — it has the whistle blown for three short blasts. These should signal boaters to return immediately. The whistle isn’t actually on Memorial Union. Rather, it’s located on the Lake Safety Tower, which is on Helen C. White Hall. It’s been there since 1987, when the Class of ’32 donated the tower as its class gift. Some years before that, it was on the opposite side of the Terrace, on the Old Boat House, which stood where One Alumni Place is now. In an era before radios were common (let alone cell phones), the whistle used a code system to notify rescue crews about where to find overturned or sinking boats. In past years, the whistle had other uses, too. In the 1940s and 1950s, it blew to announce the 10 p.m. curfew to female students. One imagines that, in those days, the whistle’s tone struck hearers as less than iconic.