Morning Frost on Snow-White: according to NASA and Lunexit - Sol 113

Caption NASA:"This image from the Surface Stereo Imager on NASA's Phoenix Mars Lander shows morning frost inside the "Snow White" trench dug by the Lander, in addition to subsurface ice exposed by use of a rasp on the floor of the trench.

The camera took this image at about 09:00 M.L.T. during the 113th Martian Day of the Mission (Sept. 18, 2008). Bright material near and below the four-by-four set of rasp holes in the upper half of the image is water-ice exposed by rasping and scraping in the trench earlier the same morning. Other bright material especially around the edges of the trench, is frost. Earlier in the mission, when the sun stayed above the horizon all night, morning frost was not evident in the trench.
This image is presented in approximately true color.
The trench is 4 to 5 centimeters (about 2 inches) deep, about 23 centimeters (9 inches) wide".