SUMMARY
The analysis of temperature data inside the soil (active layer), for the period 1998-1999/2008-2009, in an incipient rock glacier in Corral del Veleta cirque (Sierra Nevada) with presence of frozen masses in degradation process inside of it, is submitted. Thermal control covers 150 cm and data is collected at -5, -20, -50, -100 and -150 cm. This data, refined and statistically worked, shows this pattern: a very long cold period (winter) with negative values, a relatively short period with moderate temperatures (summer) and two very short periods when temperature changes form positive values to negative values (autumn) and from negative values to positive values (summer). The summer thermal pattern causes the arrival of the external shock wave at the top of the frozen underlying masses, facilitates the degradation of these underlying masses, and collapses the detrital stratum.