What is the mood of "what if a much of a which of a wind"?

This poem is a good example of a Modernist poem. Modernist writers, like e. e. cummings, often drew upon the horrors of World Wars I and II in their writing, while at the same time emphasizing and celebrating the enduring individuality and vitality of mankind. This poem was published in 1943, four years into World War II. The mood of this poem, accordingly, oscillates between the sombre and the fatalistic to the hopeful and defiant.
The sombre, fatalistic mood is identifiable throughout the poem in apocalyptic imagery such as "skies . . . hanged and oceans drowned," "a lean wind / flays screaming hills . . . / strangles valleys" and "a dawn of a doom . . . / bites this universe in two." Words like "hanged," "drowned," and "flays" connote violence and death, while the scale of the violence is emphasized by reference to "skies," "oceans," and "this universe." Overall, this imagery reflects a world deep into a second world war which, for those who lived through it, must have seemed almost apocalyptic.
On the other hand, there are moments in the poem which seem to evoke a tone at once hopeful and defiant. For example, the poet suggests that no matter how much destruction and damage there might be, "the single secret will still be man," and that man shall always have hope, symbolized by the "hello to the spring." The poet also states that "the most who die, the more we live," meaning that life, for those fortunate enough to survive, will be even more precious because of the sacrifices made by those who die.
Structurally, it is significant that the lines which evoke the more positive mood of hope and defiance are placed at the end of each stanza, after the apocalyptic descriptions of violence and chaos. Perhaps this suggests that after all the destruction, and no matter how much destruction there is, humanity will always survive, and so there will always remain the hope of a new beginning, of a new "spring."