An underground base configured for supporting an above-ground static structure that has a pair of plates each having a distal end, a proximal end, and a body portion between the distal end and the proximal end. The pair of plates are connected to each other to define a box section and a pair of flanges extending outwardly from opposing vertices of the box section. The base further has a plurality of brackets each connected to one of the plates at the proximal end, a base plate connected to the plurality of brackets, and an adjustment plate connected to the base plate via one or more adjustment fasteners. The adjustment plate is movable relative to the base plate via the one or more adjustment fasteners to adjust an orientation of the adjustment plate relative to the base plate.