Crews worked to repair the damage and clear some of the water before it could turn into sheets of ice in the frigid weather.
Police say the suspects took property from a business near 35th and North Avenue.
Anyone with any information is asked to contact Milwaukee Police at (414) 935-7360 or Crime Stoppers at (414) 224-TIPS or P3 Tips App.
The Lowlands Restaurant Group traded chili and beer -- or a hot cocoa -- for coats at the socially-distanced outdoor event.
The separate attacks happened nearly two hours apart on Milwaukee's east side and in Riverwest.