As I stepped out of my truck last night around 9pm, after attending a Cub Scout event with my son, I looked up to the sky above our house. The deep, clear blackness of the sky was spotted with stars, highlighted by Orion's Belt in the southern sky. Winter skies like this almost always precede colder mornings, as earth's heat isn't held in by cloud cover.
What I hadn't expected was the brilliant hoar frost that covered nearly every branch, bud and stem standing in our neighborhood. We will normally get a few of these frosts each winter, when the world looks like it's been dipped and frozen in confectioner's sugar. A hoar frost (a type of radiation frost) requires the combination of freezing temperatures, low winds, atmospheric moisture near the surface (often in the form of fog), and clear skies.1 When the clear skies allow the plants and other surfaces to cool more quickly that the surrounding air, the moisture crystallizes in a thick, hairy frost.
As I sit here mid-afternoon writing this, the frost has released its grip, blown by a light breeze and melted by the sun. The temperature, which hovered in single digits this morning, has quickly risen to 24 F. Photos and memory remain the only evidence the dreamlike-world painted by the frost even existed.
Although this is the time of year when gardeners begin to pine for spring, natural gifts like this morning's help to bring our focus back to the beauty and wonder of today.
(More photos can be viewed in a Shutterfly Slideshow).