In the literature on frost weathering there is a much reiterated call for spatially and temporally extensive data on the thermal regime, dilatometry, and moisture content of rock in situ. This study addresses those requirements.

Two sites were chosen for study: (1) the basin of the Dome glacier in the Canadian Rockies and (2) the campus of the University of Waterloo, Waterloo, Ontario.

The conditions of temperature and moisture content were found to vary in response to proximity to snow and ice, as well as shade and slope, but that significant S$\sb{\rm r}$ occurred as only 5% of the total number of measurements. This is reinforced by moisture content readings from vertical and horizontal rock slabs exposed at the southern Ontario site. The results indicated a more persistent record of high moisture content in the horizontal slabs, a difference that increases in winter due to snow thaw. Overall, S$\sb{\rm r}$ was only greater than 80% 5% of the time at the Dome glacier site and 0.4% at Waterloo. The correlation of a rapid freezing with the necessary moisture contents is uncommon, or occurs more rapidly than can be observed. Rock strains observed were small and generally negative, about what would be expected as a result of thermal contraction (10$\sp{-4}$ strain).

Results of freeze-thaw testing of prefractured rock indicate that the prefracturing of rock does not dramatically increase their vulnerability to freeze-thaw weathering.

In summary, these results show that, first, frost weathering conditions were not observed at all in either of the two environments selected. Second, that the dilatometric evidence showed no sign of frost weathering's effects. Third, that the effectiveness of frost weathering would not have been appreciably increased in the above examples if there had been ideal moisture and thermal conditions in addition to the prescence of pre-existing rock fractures. In general, it seems that it is simplistic to generalize about the ubiquity of this process in periglacial zones, especially from laboratory tests of mechanism.