Africa, Antarctica, frontier America and more star in this year’s Omnifest, the spring festival of giant-screen films at the Science Museum of Minnesota. Through June 20, the towering William L. McKnight-3M Omnitheater will feature a rotating roster of five large-format nature documentaries. In case this spring’s severe weather wasn’t enough for you, “Tornado Alley” probes the origins and evolution of twisters. “Wild Ocean” records the annual feeding frenzy of whales, dolphins, sharks and other large game fish along South Africa’s West Coast. Primate research gets its closeup in “Jane Goodall’s Wild Chimpanzees.” Exploration of the South Pole is the focus of “Antarctica,” and the historic expedition to the Pacific Ocean is re-created in “Lewis & Clark: Great Journey West.” With each film projected on the Omnitheater’s 90-foot domed screen, it’s a really big show. (Science Museum of Minnesota, 120 W. Kellogg Blvd., St. Paul, $7-$8, 651-221-9444 or