A portable storage silo includes a cylindrical tank of a height of the order of 45 feet and a diameter of the order of 13 feet with a filling opening at a top of the tank. The tank is raised from the ground on legs which extend to a base holding a discharge opening above the ground. The base has a transverse dimension roughly equal to that of the tank so that it is unstable in uneven terrain and four stabilizer arms are connected to the base at spaced positions around the base. Each stabilizer arm is movable from a first retracted position raised from the base to a second extended position extending outwardly to respective side of the base for stabilizing the base against tilting and is movable about an upstanding axis at the base so as to move the arm so that its angle around the base is adjustable.