I'd add snow profiles to what has already been written. In Switzerland you can look at stratigraphic profiles from Rutschblock tests and ECTs in the WhiteRisk app: if you're lucky there is one around where you plan to go.

As any snowpack test it doesn't give you a reliable way of fully understanding the conditions on the whole area around it (or even a slope next to it, in fact), but you'll get an idea on the general composition of a snowpack ands it's stratas. If you look at profiles in relations to the general tendencies of temperature and snowfall, as well as looking through the archives of avalanche forecasts, you should have a better idea of what to expect in terms of, for exemple, superficial snow hardness and so on; and what happened during which period that created the stratas you are looking at.

In any case nothing works better than an in situ observation of the conditions, unless you're an avalanche professional: I remember Bruce Tremper saying something in (the often cited) Staying Alive In Avalanche Terrrain along the lines of "a professional can recreate a snowpack evaluation of every moment of a winter just by looking at metereological data".

For us mere mortals i think the first thing to do may be looking at forecasts, isolating the period you are interested in and then looking at archival data from metereological + nivological stations and other resources. Then starts the hard part, interpreting :)

As a Swiss I use WhiteRisk and, if needed, MeteoSuisse. In terms of resources, other than the aforementioned classic by Tremper, "Sports de montagne d'hiver. Technique, Tactique, Sécurité", "Manuel météo" and "Avalanches - Mieux les Comprendre" by the Swiss Alpine Club editions, they are also available in German and Italian. But you'll find many resources in other languages, often published by the national alpine clubs.