300 km
The blood from God's wine press was 300km [180miles] long and about 1.5meters [4feet 6inches] high.
The harvest: Armageddon or the vintage of Armageddon.
The white cloud is literally the Shekinah cloud that is the presence of God.
Background Reading:
Revelation 14:14-20
The Harvest of the earth
I looked, and there before me was a white cloud, and seated on the cloud was one "like a son of man" with a crown of gold on his head and a sharp sickle in his hand. 15 Then another angel came out of the temple and called in a loud voice to him who was sitting on the cloud, "Take your sickle and reap, because the time to reap has come, for the harvest of the earth is ripe." 16 So he who was seated on the cloud swung his sickle over the earth, and the earth was harvested.
17 Another angel came out of the temple in heaven, and he too had a sharp sickle. 18 Still another angel, who had charge of the fire, came from the altar and called in a loud voice to him who had the sharp sickle, "Take your sharp sickle and gather the clusters of grapes from the earth's vine, because its grapes are ripe." 19 The angel swung his sickle on the earth, gathered its grapes and threw them into the great winepress of God';s wrath. 20 They were trampled in the winepress outside the city, and blood flowed out of the press, rising as high as the horses' bridles for a distance of 300km or 180 miles.