AdvertisementYellowstone, Grand Teton, Great Smoky Mountains Close Over Coronavirus FearsMarch 24, 2020Bobby AllynfacebookEmailYellowstone National Park's Lamar Valley near Mammoth, Wyo., on Tuesday. The National Park Service announced that Yellowstone and Grand Teton National Parks would be closed until further notice, and no visitor access will be permitted to either park. (AP)