"The hand of the Lord was on me, and he brought me out by the Spirit of the Lord and set me in the middle of a valley; it was full of bones. He led me back and forth among them, and I saw a great many bones on the floor of the valley, bones that were very dry. He asked me, 'Son of man, can these bones live?'
I said, 'Sovereign Lord, you alone know.' " -Ezekiel 37:1-3
Ezekiel knew that sometimes God relents, AND SOMETIMES HE DOESN'T! Of course God has in Himself the power to do anything, but whether it falls in His will - we do not know. Only the Sovereign Lord knows when calamity will come and when it will relent. Only God knows which wombs will open and bear children, and which will stay closed. Only Jesus knows who will be healed from cancer, and who will succumb to it. And this is a HARD LESSON to know!
"What the locust swarm has left the great locusts have eaten; what the great locusts have left the young locusts have eaten; what the young locusts have left other locusts have eaten."
"Or if I send a plague into that land and pour out my wrath on it through bloodshed, killing its people and their animals..." -Ezekiel 14:19
"To you, Lord, I call, for fire has devoured the pastures in the wilderness and flames have burned up all the trees of the field. Even the wild animals pant for you; the streams of water have dried up and fire has devoured the pastures in the wilderness." -Joel 1:19-20
"A nation has invaded my land, a mighty army without number; it has the teeth of a lion, the fangs of a lioness." -Joel 1:6
And in the bible we see that God relents from sending locusts and fire (in Amos's time), but then he sends AN EARTHQUAKE!
"This is what the Sovereign Lord showed me: He was preparing swarms of locusts after the king’s share had been harvested and just as the late crops were coming up. 2 When they had stripped the land clean, I cried out, “Sovereign Lord, forgive! How can Jacob survive? He is so small!” So the Lord relented. “This will not happen,” the Lord said. This is what the Sovereign Lord showed me: The Sovereign Lord was calling for judgment by fire; it dried up the great deep and devoured the land. 5 Then I cried out, “Sovereign Lord, I beg you, stop! How can Jacob survive? He is so small!” So the Lord relented. “This will not happen either,” the Sovereign Lord said...The words of Amos, one of the shepherds of Tekoa—the vision he saw concerning Israel two years before the earthquake." -Amos 7:1-6, 1:1
So, in conclusion, God is God and we are not. He is ruler over all, and we do not determine his deeds. However, we can join with Him in His will by prayer and study of His word. It is always better to stay on the side of the Almighty Creator than to stand against Him in rebellion.