Yes if you happen to be walking on a vent terminal
Ground frost or hoar frost.
Increase the vent to 4" as hoar frost will not over lap a 4"opening
rime, hoar
ice
Rime or hoar.
Hoar, rime
Frost is frozen dew. It can also be called rime or hoar.
Frost, hoarfrost, hoar, rime, snow
Hoar frost gets its name from the Old English word "hār," which means gray or old. It is called "hoar" because of its white, frosty appearance that can make surfaces look like they are covered in white hair or ice needles.
The closing up of a vent terminal do to warm moist vapors touching the sides of a colder surface
slip
John Hoar was born in 1622.