What is the prescribed manner for raising hands during the prayer for rain (Istisqa)?

Primary text

It is recommended to raise the hands during the supplication for rain (Istisqa). The Prophet Muhammad, peace be upon him, reportedly never raised his hands in any supplication except for the Istisqa, raising them so high that the whiteness of his armpits became visible. In another account, the Prophet raised his hands, and the people raised theirs with him. This practice is established by narrations recorded by Al-Bukhari and others.