Psalm 32: 6
Therefore, let everyone who is godly pray to Thee in a time when Thou mayest be found; surely in a flood of great waters they shall not reach him.
When should you pray in response to a calamity? Today! When you are in a crisis is no time to begin praying. It is the daily prayer, the continual prayer that helps you to be able to stand in the time of great pressure. When the challenge comes, your deep, abiding trust in the Lord arises because you have been daily praying to him.
You can hear him a lot better when you are quiet too. You need the calm, quiet time to build yourself up and to hear from Father. In a crisis is no time to try to start that. When you have laid in layer after layer of prayer in your heart and thereby drawn closer to the Lord and more secure in your relationship with him, all that prayer comes to your defense when you need it. Pray now, when you are not over-stressed so that in the time of great need your defenses are fully arrayed. Your armor will already be on you and the weapon of our warfare, the Word, will be in your heart at the ready.