White frost

From Glossary of Meteorology

white frost

  1. A relatively heavy coating of hoarfrost.

    With respect to vegetation, a white frost is less damaging than a black frost for at least two reasons: 1) it tends to insulate the plant from further cold; and 2) it releases latent heat of fusion (albeit slight) to the environment.

  2. Colloquial term for a deposit of fine rime.