Boulder, Colo. Elementary school students are dropped off at class as Winter Storm Zeus dropped snow over Boulder, Colo., Tuesday April 23, 2013. The Colorado Avalanche Information Center says avalanche danger there is considerable. (AP Photo/Brennan Linsley) Winter Storm Zeus delivered even more snow to parts of the Rockies, Plains, and Upper Midwest on April 22-23, 2013, and was promptly followed by record cold temperatures. The additional snowfall, coming on the heels of Winter Storms Walda, Xerxes and Yogi earlier...