I know that in the mountains around Grenoble there are some huts. I would like to go on a two-day hike and spend a night in such hut. I mean how much snow there is? How low can a temperature drop during the day and at night? Are there avalanches?
August is high season so the huts will be very full, particularly at weekends. It's best to book well in advance.
If you stick to the more popular marked hiking trails you are unlikely to experience much snow at that time of year. Just read the guidebook - if there are any technical passages that require equipment it will be highlighted.
Of course these are high mountains so there is always the possibility of an unseasonal blizzard. Serious storms will normally be forecast, so it's unlikely you'll be caught out.
At that time of year avalanche is not a risk on marked trails, though falling ice can be an issue on more technical routes if you decide to do some peak-bagging.
In August the temperatures can feel pretty hot, especially when ascending. A good sun hat is essential! At night at a high hut the outside temperature might drop as low as -5c. If you are crossing high passes bear this in mind when choosing your safety equipment in case you have to overnight on the mountain.
If you're used to the US West Coast, just be aware that weather in Europe is much more changeable. You can experience all kinds of conditions in a single day. So be prepared for heat, cold and rain.
If you're new to the high alps you're in for a treat. But be realistic about the limits of your experience and choose suitable trails - they are graded for difficulty and seriousness.
This is all information you can get from a plethora of online sources, but from a quick 2 minutes I found this:
- for Grenoble, a 20cm snowfall is a high average.
- Temperature change between day and night can be around 9C (+2 to -7) in winter but more like 12C in August, and the higher up you are, the colder this will get.
And yes, avalanches do happen at Les Deux Alpes...