This paper describes studies of bifurcation buckling of hyperboloids used for large-scale cooling towers. Those studies include the effects of flexible supports, combined loadings from wind, dead weight, and temperature, shell cracking, different variations in the wind pressure distribution, and changes in the shell thickening. Comparisons are made between numerical and wind-tunnel results. The finite element formulation used is examined and results are presented for the tower at the Trojan Nuclear Power Plant on the Columbia River, Oregon.