Is there any risk of wild animals or avalanche on Har ki Doon trek?
Yes, as Har ki Doon trek is a part of Govind National Park which is well known for it variety of flora and fauna so it is advised to trek with your team and do not go far from your tent alone. At night it is advised to go out with one of your trek mate.
Avalanche is a common thing in snowy mountains so you should need no to worry about it. There is a chances of avalanche in Har ki Doon valley in winter season only but most of the guide don't move forward when weather condition get worst.
