Frozen surficial sediments that are otherwise unconsolidated contain structures and characteristics that are different from those of the same sediments when in an unfrozen state. These differences are usually related to either the nature of the ice contained within the frozen sediment or to weathering processes and chemical precipitates that are associated with freezing and thawing. This paper summarizes (a) the manner in which ground freezes when a landscape experiences the onset of cold-climate conditions and (b) what happens when newly transported sediments freeze following deposition in that environment. In the absence of obvious morphological evidence, the recognition of previously-frozen sediments is problematic. Less well-understood evidence includes secondary precipitates, neoformed clay minerals, seasonal frost cracks and fragipans.