Although it can be easy to focus on the storm that starts Tuesday evening, we should not ignore the conditions we are dealing with today. Human triggered avalanches and near misses have been reported almost daily throughout the Central Mountains. So the message remains consistent and persistent. Persistent weak layers developed early in the winter and persistent slab avalanches continue to be problematic.
Near and above treeline, our most problematic layer has been a widespread persistent weak layer that formed in mid-December and was buried by storms in late December. Depending on aspect and location, you could find surface hoar, near surface facets, crusts, or some combination. None of these snow grains are known for their ability to bond well, and are notorious weak layers. Last week's storms pushed the weak layers past the tipping point. Although the layers have become less reactive in the past few days, the incoming storm will test them again. The snowpack is deep enough now in most portions of Central Mountains to smooth out ground roughness and subtle terrain features, making it easier for avalanches to become larger and travel farther. If this incoming storm meets or beats expectations, we can expect to see another natural avalanche cycle similar to what we observed in the January 6 to 7 cycle. Or possibly larger avalanche sizes.
Below treeline, cold and clear nights have faceted away the slab that formed during the January 6 to 7 storm. Loose avalanches are gouging deeper into the depth hoar near the ground. These sluffs can grow very quickly, and become big enough to knock you off of your feet. They can be dangerous if you are in the wrong spot. The incoming storm will load this weak snow structure and make the entire snowpack very sensitive.