With no ark available, Brookfield Zoo was closed on Thursday for only the third time in its history.
"With the severity of this storm and flooding conditions, we feel it is the right decision to close the zoo," Stuart Strahl, Chicago Zoological Society CEO said in a statement. "To ensure the safety of our animals and staff, the zoo will still have staff on site who will provide basic core functions, including animal care."
The zoo is planning to reopen on Friday.
The only other times Brookfield Zoo has closed were Sept. 14, 2008, following a severe rainstorm; and Feb. 2, 2011, following a snow storm.