"There are cases in which angels are manifest in 'ordinary' form, are clothed in familiar material garments, and appear to be natural phenomena.
On such occasions, the viewer will encounter difficulties in deciding whether an apparition or a natural object stands before him, whether the pillar of fire or the man he perceives belongs to this world, with its own system of natural causality, or to another.
Furthermore, the angel, that is, the force sent from a higher world, may not only be manifest in the physical world, but may also appear to act according to, and be governed by, the laws of nature, either totally or to a limited degree.
In such cases, only prophetic insight can determine whether, and to what extent, higher forces are active.
The fact that a man can create an angel, which is instantaneously transposed to another world, is not, in itself, a supernatural event.
It is a part of a day-to-day way of life that can on occasion seem ordinary and commonplace—the life of mitzvot.
When we perform an action that results in the creation of an angel, we are generally aware of no more than that we are acting on, and within, the physical world.
Similarly, the appearance of an angel does not necessarily involve a deviation from the normal laws of physical nature.
Man is thus in close contact with the upper worlds, and though the actual route, the nature of the link, is hidden, the fact of the relationship is as axiomatic as the duality of his body and soul, of matter and spirit.
Man does not pause to wonder every time he moves from the physical to the spiritual part of the World of Action, and takes for granted the occasional penetration of higher worlds into our world."
–Rabbi Adin Steinsaltz
From "Worlds, Angels and Men," p. 48 in The Strife of the Spirit by Rabbi Adin Steinsaltz