Snow cover and soil moisture controls on solifluction in an area of seasonal frost, eastern Alps

This paper presents multi-year measurements of solifluction, frost heave and the concurrent thermal and hydrological regimes at two solifluction lobes with seasonal frost in the eastern Alps, Austria. The monitoring system included a new solifluction meter and time-domain-reflectometry (TDR) probes to measure the unfrozen water content of the soil. Three phases of ground thermal and hydrological conditions were identified, each with distinct consequences for soil movements. Rapid frost heave occurred during initial ground freezing in early winter. Freezing intensity and maximum frost penetration are strongly influenced by snow drifting in that period. Another period of marked heaving during spring snowmelt is attributed to meltwater infiltration into the frozen ground. Solifluction commenced at high water contents with the beginning of thaw settlement and was enhanced by daily fluctuations of snowmelt and lateral influx of meltwater. Slow movements continued, or even started, after complete thawing of the ground as long as lateral runoff from snow patches upslope elevated soil water contents. Copyright (C) 2003 John Wiley Sons, Ltd.