Most dry slab avalanches occur during or immediately following loading by snowfall or wind deposition. In the absence of further loading avalanche activity decreases over time. This suggests that avalanche release is facilitated by changes in snowpack properties during loading, and that changes following loading generally help to stabilize the snowpack. This study quantifies these longer term stabilizing changes following loading. We developed a field method to rapidly increase the load on existing weak layers, and used the technique to add 10 cm of disaggregated snow on over 30 isolated columns. We then conducted Propagation Saw Tests (PSTs) in the minutes, hours and days following loading and isolation, with tests ranging from 15 minutes to 4 days. We filmed each test at 120 fps for particle tracking velocimetry analysis, and we utilized a finite element (FE) model to simulate the experiments and better interpret our results. We found that critical crack lengths increased rapidly at first and then more slowly over time. FE simulations of the experiments suggest that changes in critical crack length over time are caused by an increase in slab elastic modulus in the first hours following loading, and then caused by both increasing slab elastic modulus and weak layer specific fracture energy in days following loading. Our results help to illustrate changes in critical crack lengths in the days following loading, and are consistent with field observations of increasing avalanche activity immediately following loading events and decreasing avalanche activity afterwards.