This question is directed to the Prophet Muhammad (saws) and the questioner is Allah (swt). It is about the overwhelming event.
الْغَاشِيَةِ (overwhelming): A name of the judgement day because it will overwhelm the people and overcome them. Allah (swt) is exalted from asking but He (swt) gives a question to confirm the matter which is being asked about because when the questioner explains a matter, then it is an announcement, but, when he says it as a question, then the answer will be an admission from the one who is asked. This expression is a high linguistic level in Arabic language.
Allah (swt) is describing the overwhelming through the horrors that take place during it. It overwhelms the people and overcome them with its horrors, hence, there will be no escape because it comes from everywhere.