Kindly note, the railway company concerned was Matterhorn Gotthardbahn.
You can find the passenger rights for the Swiss public transport here:
However, although I completely do understand your unpleasant situation and the additional expenses caused, public transportation companies cannot made liable for unforseeable events, such as avalanches. I guess, this is also valid in your home country; thus, this is a matter for your travel insurance.
To conclude, passenger rights reject any compensation payments arising from natural disasters:
- You have no entitlement to the covering of costs of accommodation, if the transport company is not responsible for the delay or cancellation in question. For example, this applies in the event of delays or cancellations resulting from natural disasters.
- You have no entitlement to the covering of costs arising from subsequent damages, for example, if you miss a flight or concert due to a delay or cancellation.