New Defender's Study Bible Notes
147:17 casteth forth his ice. Possibly a reference to the Ice Age following the Flood (perhaps implied in Psalm 147:16). Intense cold such as this would hardly have been known in Israel at any later date.
147:18 sendeth out his word. The same divine word which controls nature (note also Psalm 148:8) speaks to His people (Psalm 147:19).