Yes, in continental snowpacks (like Colorado) weak layers such as surface hoar and depth hoar tend to form on northwest through east facing slopes. These persistent weak layers are often the culprit in the big, fatal mid-winter avalanches. Although really nasty facet/ice crust weak layers are possible on S. facing slopes, the sun on south facing slopes tends to burn off weak layers and discourage depth hoar formation. These are generalizations – do your own avalanche evaluation and play it conservative until you get a good feel for how avalanches work! Also good to consider – in the spring, extended periods of above freezing temperatures tend to turn thin lower elevation snowpacks into isothermal mush which is dangerous and tantamount to torture to slog around in. This (combination of warm temps and a thin snowpack) may have been a contributing factor here. In the spring, it is not uncommon to start out the day in scary, mushy crap snow and climb up into a bomber melt/freeze snowpack near and above treeline. Hope this helps.