Answer
The word hoarfrost is an older word for “frost.” Hoarfrost is found in the King James Version in Psalm 147:16: “[God] giveth snow like wool: he scattereth the hoarfrost like ashes.” Other occurrences of the word in the KJV are Psalm 78:47 and (using hoar frost) Exodus 16:14. Most other translations, such as the NIV and NASB, simply use the word frost.
The words hoar and hoary (found four times in the KJV but not in modern versions) refer to a whitish gray color. Hoarfrost is simply “whitish gray frost.” In other words, it is frost. Modern usage has dropped the descriptive part of the compound word. The morning frost on the grass often appears a whitish gray. The KJV speaks of the “hoary frost” in Job 38:29.
The KJV uses hoary head to speak of gray hair, but it is really an idiom that refers to old age (see Leviticus 9:32 and Proverbs 16:31). Job 41:32 uses the term hoary to refer to the color of the deep water when churned up.
The Bible speaks of the frost in Psalm 147:6 and Job 38:29 to speak of God’s creative power and control. Frost forms because of the way God created the earth’s ecosystem. Psalm 147 speaks of clouds, rain, snow, frost, hail, and wind. The processes of both freezing and melting are mentioned. In wisdom God has made all things. The conclusion of the song is a hallelujah: “Praise the Lord” (Psalm 147:20).
Frost can be beautiful, although in some cases it harms plants. But it can also be beneficial: frost can improve the flavor and sugar content of some fruits and vegetables. Frost can also kill off pests.
Hoarfrost is just one more reminder of the intricate way that God has created the world.