CREATE TABLE table_17796 ("Year" FLOAT, "Road Opened" TEXT, "Road Closed" TEXT, "Freight Carried s Tonne" FLOAT, "Super B Capacity Reached [ citation needed ]" TEXT, "Number of Truck Loads North" FLOAT)

What is thea year the road closed April 13?
SELECT MAX("Year") FROM table_17796 WHERE "Road Closed" = 'April 13'
SELECT MAX("Year") FROM "table_17796" WHERE "Road Closed" = 'April 13'