Before you head of skiing you'll want to check out the weather reports in the St Anton area. There are a number of great locations to check out the weather reports. Even the BBC website features its own resources. The BBC Weather Centre St Anton Report is featured in the Snowsports section of their website. It's a highly useful resource.
j2Ski is another great resource of information with features such as weather and snowfall for all you piste enthusiasts. Check out their 7 day weather and snowfall forecast live on their website.