Snow glide is the translational slip of the entire snow pack over a sloping ground surface. It is thought that rapid rates of snow glide precede the release of full-depth avalanches. The nature of avalanches that release at the ground makes them difficult to predict and difficult to control using explosives. The aim of this research is to determine the relationship between rapid snow glide and full-depth avalanche occurrence and to examine climate factors affecting both processes. Data collected from an instrumented site along the Coquihalla Highway in the Cascade Mountains of British Columbia were used for analysis during two winter seasons (1992-93, 1993-94). Glide is influenced by the nature of the interaction between the roughness of the ground and the snow pack, and by the distribution of water at the interface. The presence of water at the interface affects the material properties of snow and the friction conditions. The impact of freewater on glide is influenced by the volume and rates of water input. Higher glide rates and fulldepth avalanche release are the almost immediate responses to contributions of free-water. The data show that the most significant contributor is rainfall, which is common in the study area throughout the winter season. The supply of free-water from snow melt due to radiative and thermal sources of energy become more significant in the spring. Water inputs increase the thickness of the saturated layer at the base of the snow pack, allowing greater amplitudes of roughness to be overcome. By drowning or partially drowning the roughness elements, a thin film of water reduces the shear resistance of the snow pack to downslope movement. Inputs of water at rates higher than transmissions rates will increase pore pressures and decrease shear stress encouraging further downslope movement. Failure of the snow pack at the ground is translational, most often occurring 12-24 hours after a rainfall event, but sometimes much later when avalanche release would not be expected. Although there is no threshold glide velocity associated with avalanche release, it can be concluded that snow glide is a good indicator of active periods of full-depth avalanche occurrence. However, results from this study show that rainfall rates and snow melt rates may be more accurate predictors of avalanche occurrence in the study area.

Forest fires are an increasing concern under climate change. Substantially increased fire vulnerability could become a reality for many areas, including the Rocky Mountains. Forest fire hazard was examined in the upper North Saskatchewan and St. Mary watersheds for the period of 1960 to 2100. Ensemble climate scenarios were chosen to represent a wide range of possible future climates. The GENGRID meteorological model and the Canadian Forest Fire Weather index System were combined to assess possible changes in forest fire hazard in the Rocky Mountains. A wind model was developed to estimate daily wind speed variation with elevation. It was found that under most climate scenarios, fire hazard is predicted to increase. If future temperatures are warm, as expected, it could offset future precipitation increases, resulting in greater severity of fire weather and an in increase the number of days per year with high fire hazard. / xiii, 130 leaves ; 29 cm

In the British Columbia Coast Mountains most dendroclimatological and dendroglaciological studies have focused on developing insights from tree‐ring sites located in the southern and central regions. By contrast relatively few studies have been conducted in the northwestern Coast Mountains, where exploratory studies reveal that significant climate‐radial growth relationships exist. The purpose of this study was to develop a proxy record of climate change from tree rings and to reconstruct the late Holocene glacial history of two outlet glaciers spilling eastward from th e Cambria Icefield. Dendroclimate investigations were conducted using mountain hemlock (Tsuga mertensiana) trees growing on three high‐elevation montane slopes. The three stands located along a 35 km transect cross date to form a master chronology for the region spanning 409 years (1596 to 2007 A.D.). Correlation analyses show that the radial growth of the regional tree‐ring chronology corresponds to variations in the mean June‐July‐August (JJA) air temperature. The relationship between the two variables was used to reconstruct mean JJA air temperature from 1680 to 2007 A.D.). The reconstruction illustrates warm and cool intervals that are synchronous ito those derived from other paleoenvironmental research in this region. The proxy record also highlights annual to inter‐decadal climate variability likely resulting from atmospheric‐ocean circulation patterns described by the El Niño‐Southern Oscillat ion and the Pacific Decadal Oscillation. The late Holocene behaviour of White and South Flat glaciers was investigated using radiocarbon dating techniques, dendrochronological cross‐dating techniques and geomorphological analysis of sedimentary units within the White and South Flat glacier forefields. Evidence for a First Millennial Advance (FMA) cumulating around 650 A.D. and early Little Ice Age (LIA) advances at 1200 and 1400 A.D. were documented. These advances are contemporaneous with the late Holocene activity of glaciers throughout the region, suggesting coherent broad‐scale climate forcing mechanisms have influence glacial mass balance regimes over at least the last two millennia. The dendroclimatological and dendroglaciological findings of the study provide the first annually‐resolved climate record for the region and help to enhance our understanding of late‐Holocene glacier behaviour in the Cambria Icefield Area. The thesis documents the complex interactions between climate and the radial growth of mountain hemlock trees in the Pacific Northwest, and describes the role that long‐term climate variability played in glacier dynamics during the FMA and LIA. / Graduate

A multidisciplinary investigation into the timing, distribution, and intensity of tectonothermal events has resulted in an understanding of the tectonic evolution of the northeast Sacramento Mountains, in particular, and of the northern Sacramento Mountains in general. The application of geologic, structural, geochemical, and thermochronologic techniques has provided the relative and absolute timing of crustal and tectonic processes, leading to the development of a petrogenetic model for the evolution of the Sacramento Mountains metamorphic core complex. The metamorphic core complex was uplifted and cooled during Miocene detachment faulting (-23- 12 Ma). The Eagle Wash Intrusive Complex, a calc-alkalic granodioritic intrusion, was emplaced during detachment faulting at -20 Ma, at -3 kb and ~680°C. The EWIC records rapid cooling and uplift following emplacement, at rates of >100°C/Ma and 1.5-3 km/Ma, respectively. The EWIC was below ~100°C (the closure temperature of fission tracks in apatite) by 15 Ma. The structural and thermal history for the syntectonic intrusive suite is best explained via an evolving simple shear zone. The EWIC was intruded into, or proximal to, a mylonitic shear zone. The SW dip of the myonitic foliation in the EWIC could represent a primary feature of the shear zone, or the capture of a relatively older feature by a younger detachment fault splay. The later interpretation is consistent with the thermochronologic data, which suggests that faulting continued in the east after its termination in the west. Using the thermochonologic data to develop a thermal profile of the crust, the angle of faulting was calculated to be <30°C. The slip-rate associated with the detachement fault, though poorly constrained, was determined to be -4 mm/yr. This value is about half that determined from other core complexes and suggests that extension was slower here than elsewhere in the region.

Thesis (S.T.M.)--Concordia Seminary, 1989. / Includes bibliographical references (leaves 119-124).

Thesis--Université Paul-Valéry, 1973. / On cover: La population de la Cévenne languedocienne. Errata slip inserted. Includes bibliographical references (p. 415-425).

Thesis (Ph. D.)--California Institute of Technology, 1933. / Online version available on the World Wide Web.

Inaug.-diss.--Basel. / "Curriculum vitae": at end. "Literaturverzeichnis": p. 148-150.

Thesis--Université Paul-Valéry, 1973. / On cover: La population de la Cévenne languedocienne. Errata slip inserted. Includes bibliographical references (p. 415-425).

Thesis (PH. D.)--University of Michigan, 1936. / Cover title. Consists of two parts: the first part reprinted from Papers of the Michigan academy of science, arts, and letters, vol. XXIII, 1937, pub. 1938 and the second from vol. XXIV, pt. III, 1938, pub. 1939.