The Permissibility of Tayammum (Dry Ablution) When Unable to Use Water for Wudu' (Ablution)

Here is a question sent by one of the brothers from Iraq, the brother Ghazi Abd al-Khalifa. He says: My question concerns prayer. I am a middle school student living in the internal dormitory. I woke up in the morning to perform the obligatory Fajr (dawn) prayer. The weather was very cold, and I had no means to heat the water. I wiped without washing my feet with water. Is this prayer acceptable, or do you advise me to make it up?
Answer: This requires detail: If you are able to find warm water, or water that poses no danger, or to heat it from your neighbors, or to buy it from your neighbors or from others by purchase, then it is obligatory for you to do so; because Allah says: [Surat al-Taghabun: 16]. So you must do what you can of buying or heating or other means of being able to perform the lawful wudu' with water. If you are unable, or if the cold is severe for you and there is danger in it, and you have no way to heat it or to buy any hot water from what is around you, then you are excused by this if there is danger to you. You believe that there is danger to you from that in your health, by death or illness, then you are excused and you do not have to make it up. You must perform tayammum. When you wipe with water, you must perform tayammum. You must perform tayammum with dust. You strike your hand in the dust and wipe your face and your hands. This suffices for you instead of water when you are unable to use it due to its coldness and the severity of the cold, and the absence of anything to warm you or warm the water.
And you must be careful and diligent in this, fearing Allah and being mindful of Him. Yes.