That sux.
UPDATE (June 13 at 11:17 a.m.): All entrances to Yellowstone National Park CLOSED temporarily due to heavy flooding, rockslides, extremely hazardous conditions; Stay informed about road status and weather conditions!
Effective immediately, all entrances to Yellowstone National Park are temporarily CLOSED due to substantial flooding, rockslides and mudslides on roadways from recent unprecedented amounts of rainfall and flooding.
Effective immediately, no inbound visitor traffic will be allowed into the park until conditions stabilize and the park can assess damage to roads and bridges and other facilities. This includes visitors with lodging and camping reservations.