Maximum sustained wind 50% of the geostrophic wind speed aloft; while over open water or ice, the reduction is between 10% and 30%. In most basins, maximum sustained winds are used to define their category. In the Atlantic and northeast Pacific oceans, the Saffir–Simpson scale is used. This scale can be used to determine possible storm surge and damage impact on land. In most basins, the category of the tropical cyclone (for example, tropical depression, tropical storm, hurricane/typhoon, super typhoon, depression, deep depression, intense tropical cyclone) is determined from the cyclone's maximum sustained wind. Only in Australia is this quantity not used to
Ode to the West Wind a prophet who does not only bring "black rain, and fire, and hail" (28), but who "will burst" (28) it. The "locks of the approaching storm" (23) are the messengers of this bursting: the "clouds". Shelley also mentions that when the West Wind blows, it seems to be singing a funeral song about the year coming to an end and that the sky covered with a dome of clouds looks like a "sepulchre", i.e., a burial chamber or grave for the dying year or the year which is coming to an end. Shelley in this canto "expands his vision from